Add yuku parser (#19628)

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

.github/renovate.json5

@@ -60,6 +60,10 @@
       groupName: "Acorn and Espree",
       matchPackageNames: ["acorn", "acorn-jsx", "espree"],
     },
+    {
+      groupName: "Yuku parser",
+      matchPackageNames: ["yuku-parser", "@yuku-parser/*"],
+    },
     {
       groupName: "Regex related dependencies",
       matchPackageNames: ["regexp-util", "unicode-regex", "cjk-regex"],

CONTRIBUTING.md

@@ -67,7 +67,7 @@ If the list includes `typescript`, then `babel-ts`, and `oxc-ts` are included im
 
 If the list includes `flow`, then `hermes` is included implicitly.
 
-If the list includes `babel`, and the current directory is inside `tests/format/js` or `tests/format/jsx`, then `acorn`, `espree`, `meriyah`, and `oxc` are included implicitly.
+If the list includes `babel`, and the current directory is inside `tests/format/js` or `tests/format/jsx`, then `acorn`, `espree`, `meriyah`, `oxc`, and `yuku` are included implicitly.
 
 ### **`options`**
 

cspell.json

@@ -306,6 +306,7 @@
         "xtest",
         "yamafaktory",
         "Yatharth",
+        "yuku",
         "Zatorski"
     ],
     "ignoreRegExpList": [

eslint.config.js

@@ -515,6 +515,7 @@ const configs = [
         "src/language-js/parse/json.js",
         "src/language-js/parse/acorn.js",
         "src/language-js/parse/oxc.js",
+        "src/language-js/parse/yuku.js",
         "src/language-js/parse/utilities/wrap-expression.js",
       ],
       "prettier-internal-rules/prefer-create-type-check-function": [

knip.config.js

@@ -35,8 +35,9 @@ const config = {
         "buffer",
         "base64-arraybuffer-es6",
         "flow-estree",
+        "@yuku-parser/wasm",
       ],
-      ignoreBinaries: ["test-coverage"],
+      ignoreBinaries: [],
     },
     website: {
       entry: [

package.json

@@ -131,7 +131,8 @@
     "vnopts": "2.0.5",
     "wcwidth.js": "2.0.0",
     "yaml": "2.9.0",
-    "yaml-unist-parser": "3.2.0"
+    "yaml-unist-parser": "3.2.0",
+    "yuku-parser": "0.6.2"
   },
   "devDependencies": {
     "@babel/generator": "8.0.0",
@@ -140,6 +141,7 @@
     "@types/jsesc": "3.0.3",
     "@typescript-eslint/eslint-plugin": "8.64.0",
     "@typescript-eslint/parser": "8.64.0",
+    "@yuku-parser/wasm": "0.6.2",
     "base64-arraybuffer-es6": "3.1.0",
     "browserslist": "4.28.5",
     "browserslist-to-esbuild": "2.1.1",

packages/plugin-yuku/README.md

@@ -0,0 +1,56 @@
+# @prettier/plugin-yuku
+
+[![Npm Version](https://img.shields.io/npm/v/@prettier/plugin-yuku.svg?style=flat-square)](https://www.npmjs.com/package/@prettier/plugin-yuku)
+[![MIT License](https://img.shields.io/npm/l/@prettier/plugin-yuku.svg?style=flat-square)](https://github.com/prettier/prettier/blob/main/license)
+
+> Prettier [yuku](https://yuku.fyi/) plugin.
+
+## Install
+
+```bash
+yarn add --dev --exact prettier @prettier/plugin-yuku
+```
+
+## Usage
+
+Create or modify your [prettier configuration file](https://prettier.io/docs/en/configuration) to use the plugin:
+
+```js
+// prettier.config.mjs
+import * as prettierPluginYuku from "@prettier/plugin-yuku";
+
+/**
+ * @see https://prettier.io/docs/configuration
+ * @type {import("prettier").Config}
+ */
+const config = {
+  plugins: [prettierPluginYuku],
+};
+
+export default config;
+```
+
+**Requires prettier>=3.6.0**
+
+Or config explicitly
+
+```js
+// prettier.config.mjs
+import * as prettierPluginYuku from "@prettier/plugin-yuku";
+
+/**
+ * @see https://prettier.io/docs/configuration
+ * @type {import("prettier").Config}
+ */
+const config = {
+  overrides: [
+    {
+      files: ["**/*.{js,mjs,cjs,jsx}"],
+      parser: "yuku",
+      plugins: [prettierPluginYuku],
+    },
+  ],
+};
+
+export default config;
+```

packages/plugin-yuku/index.js

@@ -0,0 +1,18 @@
+import * as yukuParsers from "../../src/language-js/parse/yuku.js";
+import { estree as estreePrinter } from "../../src/language-js/printers.js";
+
+const AST_FORMAT = "estree-yuku";
+
+export const parsers = Object.fromEntries(
+  Object.entries(yukuParsers).map(([name, parser]) => [
+    name,
+    { ...parser, astFormat: AST_FORMAT },
+  ]),
+);
+
+export const printers = {
+  [AST_FORMAT]: estreePrinter,
+};
+
+export { default as options } from "../../src/language-js/options.js";
+export { default as languages } from "./languages.evaluate.js";

packages/plugin-yuku/languages.evaluate.js

@@ -0,0 +1,15 @@
+import builtinJsLanguages from "../../src/language-js/languages.evaluate.js";
+
+const replacements = new Map([["babel", "yuku"]]);
+
+const languages = builtinJsLanguages
+  .map((language) => {
+    const parsers = language.parsers
+      .map((parser) => replacements.get(parser))
+      .filter(Boolean);
+
+    return parsers.length > 0 ? { ...language, parsers } : undefined;
+  })
+  .filter(Boolean);
+
+export default languages;

packages/plugin-yuku/package.json

@@ -0,0 +1,24 @@
+{
+  "name": "@prettier/plugin-yuku",
+  "version": "0.0.0",
+  "description": "Prettier yuku plugin.",
+  "type": "module",
+  "exports": {
+    ".": {
+      "types": "./index.d.ts",
+      "browser": "./index.browser.mjs",
+      "default": "./index.mjs"
+    },
+    "./*": "./*"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/prettier/prettier.git",
+    "directory": "packages/plugin-yuku"
+  },
+  "funding": "https://github.com/prettier/prettier?sponsor=1",
+  "homepage": "https://github.com/prettier/prettier/tree/main/packages/plugin-yuku",
+  "author": "fisker Cheung <lionkay@gmail.com>",
+  "license": "MIT",
+  "sideEffects": false
+}

scripts/build-website.js

@@ -68,7 +68,7 @@ async function buildPlaygroundFiles(version) {
     for (const pluginName of ["plugin-hermes"]) {
       pluginFiles.push(`${pluginName}/index.mjs`);
     }
-    for (const pluginName of ["plugin-oxc"]) {
+    for (const pluginName of ["plugin-oxc", "plugin-yuku"]) {
       pluginFiles.push(`${pluginName}/index.browser.mjs`);
     }
   }

scripts/build/packages/index.js

@@ -1,9 +1,11 @@
 import pluginHermesBuildConfig from "./plugin-hermes.js";
 import pluginOxcBuildConfig from "./plugin-oxc.js";
+import pluginYukuBuildConfig from "./plugin-yuku.js";
 import prettierBuildConfig from "./prettier.js";
 
 export default [
   prettierBuildConfig,
   pluginHermesBuildConfig,
   pluginOxcBuildConfig,
+  pluginYukuBuildConfig,
 ];

scripts/build/packages/plugin-yuku.js

@@ -0,0 +1,104 @@
+import fs from "node:fs/promises";
+import path from "node:path";
+import { outdent } from "outdent";
+import { DIST_DIR, PACKAGES_DIRECTORY } from "../../utilities/index.js";
+import { createJavascriptModuleBuilder } from "../builders/javascript-module.js";
+import { getPackageFile } from "../utilities.js";
+import {
+  createPackageMetaFilesConfig,
+  createTypesConfig,
+} from "./config-helpers.js";
+
+const packageConfig = {
+  packageName: "@prettier/plugin-yuku",
+  sourceDirectory: path.join(PACKAGES_DIRECTORY, "plugin-yuku"),
+  distDirectory: path.join(DIST_DIR, "plugin-yuku"),
+  modules: [],
+};
+
+const mainModule = {
+  name: "Entries",
+  files: [
+    {
+      input: "index.js",
+      output: "index.mjs",
+      build: createJavascriptModuleBuilder({
+        input: "index.js",
+        output: "index.mjs",
+        format: "esm",
+        platform: "node",
+        external: ["yuku-parser"],
+        addDefaultExport: true,
+      }),
+    },
+    {
+      input: "index.js",
+      output: "index.browser.mjs",
+      build: createJavascriptModuleBuilder({
+        format: "esm",
+        platform: "universal",
+        addDefaultExport: true,
+        replaceModule: [
+          {
+            module: getPackageFile("yuku-parser"),
+            path: getPackageFile("@yuku-parser/wasm"),
+          },
+          {
+            module: getPackageFile("@yuku-parser/wasm"),
+            async process(text) {
+              const wasmUrlPattern =
+                /const wasmUrl = new URL\("(?<wasmFile>.\/.+\.wasm)", import\.meta\.url\);/;
+              const { wasmFile } = text.match(wasmUrlPattern).groups;
+              const wasmBase64String = await fs.readFile(
+                getPackageFile(`@yuku-parser/wasm/${wasmFile}`),
+                "base64",
+              );
+
+              text = text.replace('import("node:fs/promises")', "whatever");
+              text = text.replace(wasmUrlPattern, "");
+
+              text = text.replace(
+                "const { memory, alloc, free, parse: wasmParse } = (await instantiate()).exports;",
+                outdent`
+                  const module = new WebAssembly.Module((wasmBinary));
+                  const instance = new WebAssembly.Instance(module);
+                  const { memory, alloc, free, parse: wasmParse } = instance.exports;
+                `,
+              );
+
+              text = outdent`
+                import { decode as __decode } from "base64-arraybuffer-es6";
+                const __base64ToArrayBuffer = Uint8Array.fromBase64
+                  ? (string) => Uint8Array.fromBase64(string).buffer
+                  : __decode;
+                const wasmBinary = /* "${wasmFile}" */ __base64ToArrayBuffer(${JSON.stringify(wasmBase64String)});
+
+                ${text}
+              `;
+
+              return text;
+            },
+          },
+        ],
+      }),
+      playground: true,
+    },
+    ...createTypesConfig({ input: "index.js", isPlugin: true }),
+  ],
+};
+
+packageConfig.modules.push(
+  mainModule,
+  createPackageMetaFilesConfig({
+    "package.json"(packageJson, { projectPackageJson }) {
+      return {
+        ...packageJson,
+        dependencies: {
+          "yuku-parser": projectPackageJson.dependencies["yuku-parser"],
+        },
+      };
+    },
+  }),
+);
+
+export default packageConfig;

scripts/production-eslint-config.js

@@ -28,6 +28,7 @@ const nodejsFiles = jsFiles.filter(
       "dist/prettier/internal/experimental-cli.mjs",
       "dist/prettier/internal/experimental-cli-worker.mjs",
       "dist/plugin-oxc/index.mjs",
+      "dist/plugin-yuku/index.mjs",
     ].includes(file),
 );
 

src/language-js/parse/index.js

@@ -7,3 +7,4 @@ export * from "./hermes.js";
 export * from "./meriyah.js";
 export * from "./oxc.js";
 export * from "./typescript.js";
+export * from "./yuku.js";

src/language-js/parse/oxc.js

@@ -69,7 +69,7 @@ function parseJs(text, options) {
   const sourceType = getSourceType(filepath);
 
   if (typeof filepath !== "string") {
-    filepath = "prettier.tsx";
+    filepath = "prettier.jsx";
   }
   const combinations = (
     sourceType ? [sourceType] : SOURCE_TYPE_COMBINATIONS

src/language-js/parse/postprocess/index.js

@@ -45,7 +45,15 @@ const isNodeWithRaw = createTypeCheckFunction([
 /**
 @param {{
   text: string,
-  astType?: "espree" | "flow" | "hermes" | "meriyah" | "oxc-js" | "oxc-ts" | "typescript",
+  astType?:
+    | "espree"
+    | "flow"
+    | "hermes"
+    | "meriyah"
+    | "oxc-js"
+    | "oxc-ts"
+    | "typescript"
+    | "yuku-js",
 }} options
 */
 function postprocess(ast, options) {
@@ -65,7 +73,7 @@ function postprocess(ast, options) {
   }
 
   if (ast.hashbang) {
-    if (isOxcTs) {
+    if (isOxcTs || astType === "yuku-js") {
       comments.unshift(ast.hashbang);
     }
     delete ast.hashbang;

src/language-js/parse/yuku.js

@@ -0,0 +1,89 @@
+import indexToPosition from "index-to-position";
+import { parse as yukuParse } from "yuku-parser";
+import createError from "../../common/parser-create-error.js";
+import { tryCombinationsSync } from "../../utilities/try-combinations.js";
+import postprocess from "./postprocess/index.js";
+import createParser from "./utilities/create-parser.js";
+import {
+  getSourceType,
+  SOURCE_TYPE_COMBINATIONS,
+} from "./utilities/source-types.js";
+
+/** @import {ParseOptions} from "yuku-parser" */
+
+function createParseError(error, { text }) {
+  if (typeof error?.start !== "number" || typeof error?.end !== "number") {
+    return error;
+  }
+
+  const { message, start: startIndex, end: endIndex } = error;
+
+  const [start, end] = [startIndex, endIndex].map((index) =>
+    indexToPosition(text, index, { oneBased: true }),
+  );
+
+  return createError(message, {
+    loc: {
+      start,
+      end,
+    },
+    cause: error,
+  });
+}
+
+/**
+@param {string} text
+@param {ParseOptions} options
+*/
+function parseWithOptions(text, options) {
+  const result = yukuParse(text, {
+    preserveParens: true,
+    allowReturnOutsideFunction: true,
+    semanticErrors: false,
+    attachComments: false,
+    ...options,
+  });
+
+  const { diagnostics: errors } = result;
+  for (const error of errors) {
+    throw createParseError(error, { text });
+  }
+
+  return result;
+}
+
+function parseJs(text, options) {
+  const filepath = options?.filepath;
+  const sourceType = getSourceType(filepath);
+
+  const combinations = (
+    sourceType ? [sourceType] : SOURCE_TYPE_COMBINATIONS
+  ).map(
+    (sourceType) => () =>
+      parseWithOptions(text, {
+        sourceType: sourceType === "commonjs" ? "script" : sourceType,
+        lang: "jsx",
+      }),
+  );
+
+  let result;
+  try {
+    result = tryCombinationsSync(combinations);
+  } catch ({
+    // @ts-expect-error -- expected
+    errors: [error],
+  }) {
+    throw error;
+  }
+
+  const { program: ast, comments } = result;
+
+  // @ts-expect-error -- expected
+  ast.comments = comments;
+
+  return postprocess(ast, { text, astType: "yuku-js" });
+}
+
+const yuku = /* @__PURE__ */ createParser(parseJs);
+
+export { yuku };

src/language-js/print/key.js

@@ -122,6 +122,7 @@ function isKeySafeToUnquote(node, options) {
     (parser === "babel" ||
       parser === "acorn" ||
       parser === "oxc" ||
+      parser === "yuku" ||
       parser === "espree" ||
       parser === "meriyah" ||
       parser === "__babel_estree") &&

src/main/plugins/builtin-plugins/development-plugins.js

@@ -79,6 +79,7 @@ export const plugins = /* @__PURE__ */ toLazyLoadPlugins(
       "oxc",
       "oxc-ts",
       "typescript",
+      "yuku",
     ],
   },
   {

src/main/range.js

@@ -171,6 +171,7 @@ function isSourceElement(opts, node, parentNode) {
     case "meriyah":
     case "oxc":
     case "oxc-ts":
+    case "yuku":
     case "__babel_estree":
       return isJsSourceElement(node.type, parentNode?.type);
     case "json":

tests/config/browser-prettier/main.js

@@ -20,6 +20,7 @@ const esmFiles = {
     "prettier/plugins/meriyah.mjs",
     "plugin-hermes/index.mjs",
     "plugin-oxc/index.browser.mjs",
+    "plugin-yuku/index.browser.mjs",
   ],
 };
 const umdFiles = {
@@ -38,9 +39,10 @@ const umdFiles = {
     "prettier/plugins/yaml.js",
     "prettier/plugins/flow.js",
     "prettier/plugins/meriyah.js",
-    // These two plugins don't have UMD version
+    // These plugins don't have UMD version
     "plugin-hermes/index.mjs",
     "plugin-oxc/index.browser.mjs",
+    "plugin-yuku/index.browser.mjs",
   ],
 };
 

tests/config/format-test/failed-format-tests.js

@@ -89,6 +89,7 @@ const disabledTests = new Map(
     ],
     oxc: [],
     "oxc-ts": ["typescript/typescript-only/"],
+    yuku: [],
     hermes: [
       ...commentClosureTypecaseTests,
 

tests/config/format-test/get-parsers.js

@@ -17,7 +17,7 @@ function getParsers(dirname, parsers) {
     parsers.includes("babel") &&
     (isLanguage(dirname, "js") || isLanguage(dirname, "jsx"))
   ) {
-    addParsers("acorn", "espree", "meriyah", "oxc");
+    addParsers("acorn", "espree", "meriyah", "oxc", "yuku");
   }
 
   if (parsers.includes("typescript")) {

tests/config/format-test/verify-fixtures.js

@@ -59,7 +59,7 @@ const categoryParsers = new Map([
   [
     "js",
     {
-      parsers: ["babel", "acorn", "espree", "meriyah", "oxc"],
+      parsers: ["babel", "acorn", "espree", "meriyah", "oxc", "yuku"],
       verifyParsers: [
         "babel",
         "acorn",
@@ -67,6 +67,7 @@ const categoryParsers = new Map([
         "meriyah",
         "oxc",
         "oxc-ts",
+        "yuku",
         "flow",
         "babel-flow",
         "typescript",
@@ -102,6 +103,7 @@ const categoryParsers = new Map([
         "hermes",
         "oxc",
         "oxc-ts",
+        "yuku",
       ],
       verifyParsers: [
         "babel",
@@ -117,6 +119,7 @@ const categoryParsers = new Map([
         "hermes",
         "oxc",
         "oxc-ts",
+        "yuku",
       ],
       extensions: [".js", ".jsx"],
     },

tests/format/js/_errors_/class-property-named-constructor/__snapshots__/format.test.js.snap

@@ -90,6 +90,14 @@ exports[`snippet: #0 format[typescript] 1`] = `
 Cause: '(' expected."
 `;
 
+exports[`snippet: #0 format[yuku] 1`] = `
+"Expected '(' for getter/setter definition, but found '}' (3:1)
+  1 | class Foo {
+  2 |   constructor
+> 3 | }
+    | ^"
+`;
+
 exports[`snippet: #1 format[acorn] 1`] = `
 "Classes can't have a field named 'constructor' (2:3)
   1 | class Foo {
@@ -180,6 +188,14 @@ exports[`snippet: #1 format[typescript] 1`] = `
 Cause: Classes may not have a field named 'constructor'."
 `;
 
+exports[`snippet: #1 format[yuku] 1`] = `
+"Expected '(' for getter/setter definition, but found '}' (3:1)
+  1 | class Foo {
+  2 |   'constructor'
+> 3 | }
+    | ^"
+`;
+
 exports[`snippet: #2 format[acorn] 1`] = `
 "Classes can't have a field named 'constructor' (2:3)
   1 | class Foo {
@@ -270,6 +286,14 @@ exports[`snippet: #2 format[typescript] 1`] = `
 Cause: Classes may not have a field named 'constructor'."
 `;
 
+exports[`snippet: #2 format[yuku] 1`] = `
+"Expected '(' for getter/setter definition, but found '}' (3:1)
+  1 | class Foo {
+  2 |   'constructor'
+> 3 | }
+    | ^"
+`;
+
 exports[`snippet: #3 format[acorn] 1`] = `
 "Unexpected token (2:12)
   1 | class Foo {
@@ -360,6 +384,14 @@ exports[`snippet: #3 format[typescript] 1`] = `
 Cause: Classes may not have a field named 'constructor'."
 `;
 
+exports[`snippet: #3 format[yuku] 1`] = `
+"Expected '(' for getter/setter definition, but found '}' (3:1)
+  1 | class Foo {
+  2 |   accessor 'constructor'
+> 3 | }
+    | ^"
+`;
+
 exports[`snippet: #4 format[acorn] 1`] = `
 "Unexpected token (2:12)
   1 | class Foo {
@@ -450,6 +482,14 @@ exports[`snippet: #4 format[typescript] 1`] = `
 Cause: Classes may not have a field named 'constructor'."
 `;
 
+exports[`snippet: #4 format[yuku] 1`] = `
+"Expected '(' for getter/setter definition, but found '}' (3:1)
+  1 | class Foo {
+  2 |   accessor 'constructor'
+> 3 | }
+    | ^"
+`;
+
 exports[`snippet: #5 format[acorn] 1`] = `
 "Unexpected token (2:12)
   1 | class Foo {
@@ -539,3 +579,11 @@ exports[`snippet: #5 format[typescript] 1`] = `
     | ^
 Cause: '(' expected."
 `;
+
+exports[`snippet: #5 format[yuku] 1`] = `
+"Expected '(' for getter/setter definition, but found '}' (3:1)
+  1 | class Foo {
+  2 |   accessor constructor
+> 3 | }
+    | ^"
+`;

tests/format/js/_errors_/class-property-named-constructor/format.test.js

@@ -14,6 +14,7 @@ runFormatTest(
     "babel-ts",
     "oxc",
     "oxc-ts",
+    "yuku",
     "flow",
     "hermes",
   ],

tests/format/js/_errors_/discard-binding/__snapshots__/format.test.js.snap

@@ -80,6 +80,15 @@ exports[`invalid-array-expression.js format[typescript] 1`] = `
 Cause: Expression expected."
 `;
 
+exports[`invalid-array-expression.js format[yuku] 1`] = `
+"Unexpected token ']' (1:9)
+> 1 | ([[[void], x, ], y]);
+    |         ^
+  2 |
+  3 | ([[[x], void, ], y]);
+  4 |"
+`;
+
 exports[`invalid-assignment-expression.js format[acorn] 1`] = `
 "Unexpected token (1:6)
 > 1 | void = 0;
@@ -144,6 +153,13 @@ exports[`invalid-assignment-expression.js format[typescript] 1`] = `
 Cause: Expression expected."
 `;
 
+exports[`invalid-assignment-expression.js format[yuku] 1`] = `
+"Unexpected token '=' (1:6)
+> 1 | void = 0;
+    |      ^
+  2 |"
+`;
+
 exports[`invalid-assignment-for.js format[acorn] 1`] = `
 "Unexpected token (1:15)
 > 1 | for (void of []);
@@ -208,6 +224,13 @@ exports[`invalid-assignment-for.js format[typescript] 1`] = `
 Cause: An element access expression should take an argument."
 `;
 
+exports[`invalid-assignment-for.js format[yuku] 1`] = `
+"Unexpected token ']' (1:15)
+> 1 | for (void of []);
+    |               ^
+  2 |"
+`;
+
 exports[`invalid-assignment-pattern.js format[acorn] 1`] = `
 "Unexpected keyword 'void' (3:14)
   1 | {
@@ -304,6 +327,17 @@ exports[`invalid-assignment-pattern.js format[typescript] 1`] = `
 Cause: Identifier expected. 'void' is a reserved word that cannot be used here."
 `;
 
+exports[`invalid-assignment-pattern.js format[yuku] 1`] = `
+"'void' is reserved and cannot be used as a binding identifier (3:14)
+  1 | {
+  2 |   // function parameter
+> 3 |   function f(void = 0) {}
+    |              ^^^^
+  4 | }
+  5 | {
+  6 |   // arrow function parameter"
+`;
+
 exports[`invalid-async-call-argument.js format[acorn] 1`] = `
 "Unexpected token (1:11)
 > 1 | async(void, x);
@@ -384,6 +418,15 @@ exports[`invalid-async-call-argument.js format[typescript] 1`] = `
 Cause: Expression expected."
 `;
 
+exports[`invalid-async-call-argument.js format[yuku] 1`] = `
+"Unexpected token ',' (1:11)
+> 1 | async(void, x);
+    |           ^
+  2 |
+  3 | async(x, void);
+  4 |"
+`;
+
 exports[`invalid-catch-parameter.js format[acorn] 1`] = `
 "Unexpected keyword 'void' (1:15)
 > 1 | try {} catch (void) {}
@@ -448,6 +491,13 @@ exports[`invalid-catch-parameter.js format[typescript] 1`] = `
 Cause: Identifier expected. 'void' is a reserved word that cannot be used here."
 `;
 
+exports[`invalid-catch-parameter.js format[yuku] 1`] = `
+"'void' is reserved and cannot be used as a binding identifier (1:15)
+> 1 | try {} catch (void) {}
+    |               ^^^^
+  2 |"
+`;
+
 exports[`invalid-lone-arrow-function-parameter.js format[acorn] 1`] = `
 "Unexpected token (1:6)
 > 1 | void => {}
@@ -512,6 +562,13 @@ exports[`invalid-lone-arrow-function-parameter.js format[typescript] 1`] = `
 Cause: Expression expected."
 `;
 
+exports[`invalid-lone-arrow-function-parameter.js format[yuku] 1`] = `
+"Unexpected token '=>' (1:6)
+> 1 | void => {}
+    |      ^^
+  2 |"
+`;
+
 exports[`invalid-lone-async-arrow-function-parameter.js format[acorn] 1`] = `
 "Unexpected token (1:7)
 > 1 | async void => {}
@@ -576,6 +633,13 @@ exports[`invalid-lone-async-arrow-function-parameter.js format[typescript] 1`] =
 Cause: Unexpected keyword or identifier."
 `;
 
+exports[`invalid-lone-async-arrow-function-parameter.js format[yuku] 1`] = `
+"'void' is reserved and cannot be used as an identifier (1:7)
+> 1 | async void => {}
+    |       ^^^^
+  2 |"
+`;
+
 exports[`invalid-object-expression.js format[acorn] 1`] = `
 "Unexpected token (1:22)
 > 1 | ({ p: { p: { p: void }, x, }, y});
@@ -656,6 +720,15 @@ exports[`invalid-object-expression.js format[typescript] 1`] = `
 Cause: Expression expected."
 `;
 
+exports[`invalid-object-expression.js format[yuku] 1`] = `
+"Unexpected token '}' (1:22)
+> 1 | ({ p: { p: { p: void }, x, }, y});
+    |                      ^
+  2 |
+  3 | ({ p: { x: { x }, p: void, }, y});
+  4 |"
+`;
+
 exports[`invalid-parenthesized-assignment.js format[acorn] 1`] = `
 "Unexpected token (1:7)
 > 1 | [(void)] = [];
@@ -720,6 +793,13 @@ exports[`invalid-parenthesized-assignment.js format[typescript] 1`] = `
 Cause: Expression expected."
 `;
 
+exports[`invalid-parenthesized-assignment.js format[yuku] 1`] = `
+"Unexpected token ')' (1:7)
+> 1 | [(void)] = [];
+    |       ^
+  2 |"
+`;
+
 exports[`invalid-parenthesized-binding.js format[acorn] 1`] = `
 "Unexpected token (1:10)
 > 1 | const [, (void), ] = value;
@@ -784,6 +864,13 @@ exports[`invalid-parenthesized-binding.js format[typescript] 1`] = `
 Cause: Array element destructuring pattern expected."
 `;
 
+exports[`invalid-parenthesized-binding.js format[yuku] 1`] = `
+"Unexpected token ')' (1:15)
+> 1 | const [, (void), ] = value;
+    |               ^
+  2 |"
+`;
+
 exports[`invalid-rest-element-array-pattern.js format[acorn] 1`] = `
 "Unexpected keyword 'void' (2:12)
   1 | {
@@ -872,6 +959,16 @@ exports[`invalid-rest-element-array-pattern.js format[typescript] 1`] = `
 Cause: Identifier expected. 'void' is a reserved word that cannot be used here."
 `;
 
+exports[`invalid-rest-element-array-pattern.js format[yuku] 1`] = `
+"Unexpected token ']' (2:17)
+  1 | {
+> 2 |   var [ ...void ] = [];
+    |                 ^
+  3 | }
+  4 | {
+  5 |   for (var [...void] of [[]]);"
+`;
+
 exports[`invalid-rest-element-array-pattern-for-lhs.js format[acorn] 1`] = `
 "Unexpected token (1:16)
 > 1 | for ([ ...void ] of []);
@@ -936,6 +1033,13 @@ exports[`invalid-rest-element-array-pattern-for-lhs.js format[typescript] 1`] =
 Cause: Expression expected."
 `;
 
+exports[`invalid-rest-element-array-pattern-for-lhs.js format[yuku] 1`] = `
+"Unexpected token ']' (1:16)
+> 1 | for ([ ...void ] of []);
+    |                ^
+  2 |"
+`;
+
 exports[`invalid-rest-element-array-pattern-lhs.js format[acorn] 1`] = `
 "Unexpected token (1:12)
 > 1 | ([ ...void ] = []);
@@ -1000,6 +1104,13 @@ exports[`invalid-rest-element-array-pattern-lhs.js format[typescript] 1`] = `
 Cause: Expression expected."
 `;
 
+exports[`invalid-rest-element-array-pattern-lhs.js format[yuku] 1`] = `
+"Unexpected token ']' (1:12)
+> 1 | ([ ...void ] = []);
+    |            ^
+  2 |"
+`;
+
 exports[`invalid-rest-element-object-pattern.js format[acorn] 1`] = `
 "Unexpected keyword 'void' (2:12)
   1 | {
@@ -1088,6 +1199,16 @@ exports[`invalid-rest-element-object-pattern.js format[typescript] 1`] = `
 Cause: ':' expected."
 `;
 
+exports[`invalid-rest-element-object-pattern.js format[yuku] 1`] = `
+"Unexpected token '}' (2:17)
+  1 | {
+> 2 |   var { ...void } = {};
+    |                 ^
+  3 | }
+  4 | {
+  5 |   for (var { ...void } of [{}]);"
+`;
+
 exports[`invalid-rest-element-object-pattern-for-lhs.js format[acorn] 1`] = `
 "Unexpected token (1:16)
 > 1 | for ({ ...void } of []);
@@ -1152,6 +1273,13 @@ exports[`invalid-rest-element-object-pattern-for-lhs.js format[typescript] 1`] =
 Cause: Expression expected."
 `;
 
+exports[`invalid-rest-element-object-pattern-for-lhs.js format[yuku] 1`] = `
+"Unexpected token '}' (1:16)
+> 1 | for ({ ...void } of []);
+    |                ^
+  2 |"
+`;
+
 exports[`invalid-rest-element-object-pattern-lhs.js format[acorn] 1`] = `
 "Unexpected token (1:12)
 > 1 | ({ ...void } = {});
@@ -1216,6 +1344,13 @@ exports[`invalid-rest-element-object-pattern-lhs.js format[typescript] 1`] = `
 Cause: Expression expected."
 `;
 
+exports[`invalid-rest-element-object-pattern-lhs.js format[yuku] 1`] = `
+"Unexpected token '}' (1:12)
+> 1 | ({ ...void } = {});
+    |            ^
+  2 |"
+`;
+
 exports[`invalid-sequence-expression.js format[acorn] 1`] = `
 "Unexpected token (1:6)
 > 1 | (void, x);
@@ -1296,6 +1431,15 @@ exports[`invalid-sequence-expression.js format[typescript] 1`] = `
 Cause: Expression expected."
 `;
 
+exports[`invalid-sequence-expression.js format[yuku] 1`] = `
+"Unexpected token ',' (1:6)
+> 1 | (void, x);
+    |      ^
+  2 |
+  3 | (x, void);
+  4 |"
+`;
+
 exports[`invalid-variable-declarator.js format[acorn] 1`] = `
 "Unexpected keyword 'void' (2:7)
   1 | {
@@ -1383,3 +1527,13 @@ exports[`invalid-variable-declarator.js format[typescript] 1`] = `
   5 |   let void = f(), void = g();
 Cause: 'void' is not allowed as a variable declaration name."
 `;
+
+exports[`invalid-variable-declarator.js format[yuku] 1`] = `
+"'void' is reserved and cannot be used as a binding identifier (2:7)
+  1 | {
+> 2 |   var void = f();
+    |       ^^^^
+  3 | }
+  4 | {
+  5 |   let void = f(), void = g();"
+`;

tests/format/js/_errors_/discard-binding/format.test.js

@@ -6,5 +6,6 @@ runFormatTest(import.meta, [
   "meriyah",
   "oxc",
   "oxc-ts",
+  "yuku",
   "hermes",
 ]);

tests/format/js/_errors_/export-name/__snapshots__/format.test.js.snap

@@ -84,6 +84,12 @@ exports[`snippet: #0 format[oxc-ts] 1`] = `
     |          ^^^^^^^^"
 `;
 
+exports[`snippet: #0 format[yuku] 1`] = `
+"An export name cannot include a unicode lone surrogate (1:10)
+> 1 | import { "\\uD83C" as b } from "./foo";
+    |          ^^^^^^^^"
+`;
+
 exports[`snippet: #1 format[__babel_estree] 1`] = `
 "An export name cannot include a lone surrogate, found '\\ud83c'. (1:10)
 > 1 | export { "\\uD83C" } from "./foo";
@@ -168,6 +174,12 @@ exports[`snippet: #1 format[oxc-ts] 1`] = `
     |          ^^^^^^^^"
 `;
 
+exports[`snippet: #1 format[yuku] 1`] = `
+"An export name cannot include a unicode lone surrogate (1:10)
+> 1 | export { "\\uD83C" } from "./foo";
+    |          ^^^^^^^^"
+`;
+
 exports[`snippet: #2 format[__babel_estree] 1`] = `
 "An export name cannot include a lone surrogate, found '\\ud83c'. (1:10)
 > 1 | export { "\\uD83C" as b } from "./foo";
@@ -252,6 +264,12 @@ exports[`snippet: #2 format[oxc-ts] 1`] = `
     |          ^^^^^^^^"
 `;
 
+exports[`snippet: #2 format[yuku] 1`] = `
+"An export name cannot include a unicode lone surrogate (1:10)
+> 1 | export { "\\uD83C" as b } from "./foo";
+    |          ^^^^^^^^"
+`;
+
 exports[`snippet: #3 format[__babel_estree] 1`] = `
 "An export name cannot include a lone surrogate, found '\\ud83c'. (1:15)
 > 1 | export { b as "\\uD83C" } from "./foo";
@@ -335,3 +353,9 @@ exports[`snippet: #3 format[oxc-ts] 1`] = `
 > 1 | export { b as "\\uD83C" } from "./foo";
     |               ^^^^^^^^"
 `;
+
+exports[`snippet: #3 format[yuku] 1`] = `
+"An export name cannot include a unicode lone surrogate (1:15)
+> 1 | export { b as "\\uD83C" } from "./foo";
+    |               ^^^^^^^^"
+`;

tests/format/js/_errors_/export-name/format.test.js

@@ -22,5 +22,6 @@ runFormatTest(
     "hermes",
     "oxc",
     "oxc-ts",
+    "yuku",
   ],
 );

tests/format/js/_errors_/newline-before-arrow/__snapshots__/format.test.js.snap

@@ -79,3 +79,11 @@ exports[`newline-before-arrow.js format[typescript] 1`] = `
   3 |
 Cause: Unexpected keyword or identifier."
 `;
+
+exports[`newline-before-arrow.js format[yuku] 1`] = `
+"Expected a semicolon or an implicit semicolon after a statement, but found 'x' (1:7)
+> 1 | async x
+    |       ^
+  2 | => x
+  3 |"
+`;

tests/format/js/_errors_/newline-before-arrow/format.test.js

@@ -8,4 +8,5 @@ runFormatTest(import.meta, [
   "meriyah",
   "babel-ts",
   "oxc",
+  "yuku",
 ]);

tests/format/js/_errors_/reserved-word/__snapshots__/format.test.js.snap

@@ -84,6 +84,12 @@ exports[`snippet: #0 format[typescript] 1`] = `
 Cause: Declaration or statement expected."
 `;
 
+exports[`snippet: #0 format[yuku] 1`] = `
+"Keywords cannot contain escape characters (1:8)
+> 1 | export asyn\\u{63} from "async";
+    |        ^^^^^^^^^^"
+`;
+
 exports[`snippet: #1 format[acorn] 1`] = `
 "The keyword 'interface' is reserved (1:8)
 > 1 | import interface from "foo";

tests/format/js/_errors_/reserved-word/format.test.js

@@ -36,5 +36,6 @@ runFormatTest(
     "hermes",
     "oxc",
     "oxc-ts",
+    "yuku",
   ],
 );

tests/format/js/arrows-bind/__snapshots__/format.test.js.snap

@@ -55,3 +55,12 @@ exports[`arrows-bind.js format[oxc] 1`] = `
   3 | a::(b => c);
   4 |"
 `;
+
+exports[`arrows-bind.js format[yuku] 1`] = `
+"Expected ',' or ')' in parenthesized expression, but found ':' (1:9)
+> 1 | a => ({}::b()\`\`[''].c++ && 0 ? 0 : 0);
+    |         ^
+  2 | (a => b)::c;
+  3 | a::(b => c);
+  4 |"
+`;

tests/format/js/arrows-bind/format.test.js

@@ -5,5 +5,6 @@ runFormatTest(import.meta, ["babel"], {
     meriyah: true,
     oxc: true,
     "oxc-ts": true,
+    yuku: true,
   },
 });

tests/format/js/async-do-expressions/__snapshots__/format.test.js.snap

@@ -93,3 +93,12 @@ exports[`async-do-expressions.js format[oxc] 1`] = `
   3 | };
   4 |"
 `;
+
+exports[`async-do-expressions.js format[yuku] 1`] = `
+"Expected a semicolon or an implicit semicolon after a statement, but found 'do' (1:7)
+> 1 | async do {
+    |       ^^
+  2 |   1;
+  3 | };
+  4 |"
+`;

tests/format/js/async-do-expressions/format.test.js

@@ -5,5 +5,6 @@ runFormatTest(import.meta, ["babel"], {
     meriyah: true,
     oxc: true,
     "oxc-ts": true,
+    yuku: true,
   },
 });

tests/format/js/babel-plugins/__snapshots__/format.test.js.snap

@@ -46,6 +46,13 @@ exports[`async-do-expressions.js format[oxc] 1`] = `
   2 |"
 `;
 
+exports[`async-do-expressions.js format[yuku] 1`] = `
+"Expected a semicolon or an implicit semicolon after a statement, but found 'do' (1:7)
+> 1 | async do { await requestAPI().json() };
+    |       ^^
+  2 |"
+`;
+
 exports[`async-generators.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-ts", "babel-flow"]
@@ -681,6 +688,17 @@ exports[`destructuring-private.js format[oxc] 1`] = `
   8 |   equals({ #x: otherX }) {"
 `;
 
+exports[`destructuring-private.js format[yuku] 1`] = `
+"Unexpected token '#x' as property key (5:13)
+  3 |   constructor() {
+  4 |     console.log(this.#x); // => 1
+> 5 |     const { #x: x } = this;
+    |             ^^
+  6 |     console.log(x); // => 1
+  7 |   }
+  8 |   equals({ #x: otherX }) {"
+`;
+
 exports[`discard-binding.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-ts", "babel-flow"]
@@ -725,6 +743,13 @@ exports[`discard-binding.js format[oxc] 1`] = `
   2 |"
 `;
 
+exports[`discard-binding.js format[yuku] 1`] = `
+"Unexpected token ']' (1:15)
+> 1 | const [a, void] = iter;
+    |               ^
+  2 |"
+`;
+
 exports[`do-expressions.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-ts", "babel-flow"]
@@ -805,6 +830,17 @@ exports[`do-expressions.js format[oxc] 1`] = `
   6 |   } else {"
 `;
 
+exports[`do-expressions.js format[yuku] 1`] = `
+"'do' is reserved and cannot be used as an identifier (3:9)
+  1 | // https://babeljs.io/docs/babel-plugin-proposal-do-expressions
+  2 |
+> 3 | let a = do {
+    |         ^^
+  4 |   if(x > 10) {
+  5 |     'big';
+  6 |   } else {"
+`;
+
 exports[`dynamic-import.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-ts", "babel-flow"]
@@ -935,6 +971,15 @@ exports[`export-default-from.js format[oxc] 1`] = `
   5 |"
 `;
 
+exports[`export-default-from.js format[yuku] 1`] = `
+"Expected declaration after 'export', but found 'v' (4:8)
+  2 |
+  3 |
+> 4 | export v from 'mod';
+    |        ^
+  5 |"
+`;
+
 exports[`export-namespace-from.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-ts", "babel-flow"]
@@ -1028,6 +1073,15 @@ exports[`flow.js format[oxc] 1`] = `
   4 |"
 `;
 
+exports[`flow.js format[yuku] 1`] = `
+"Expected ')' to close parameter list, but found ':' (3:17)
+  1 | // https://babeljs.io/docs/babel-preset-flow
+  2 |
+> 3 | function foo(one: any, two: number, three?): string {}
+    |                 ^
+  4 |"
+`;
+
 exports[`function-bind.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-ts", "babel-flow"]
@@ -1119,6 +1173,17 @@ exports[`function-bind.js format[oxc] 1`] = `
   6 |"
 `;
 
+exports[`function-bind.js format[yuku] 1`] = `
+"Unexpected token ':' (3:5)
+  1 | // https://babeljs.io/docs/babel-plugin-proposal-function-bind
+  2 |
+> 3 | obj::func
+    |     ^
+  4 | // is equivalent to:
+  5 | func.bind(obj)
+  6 |"
+`;
+
 exports[`function-sent.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-ts", "babel-flow"]
@@ -1197,6 +1262,17 @@ exports[`function-sent.js format[oxc] 1`] = `
   7 |"
 `;
 
+exports[`function-sent.js format[yuku] 1`] = `
+"Expected '(' to start parameter list, but found '.' (4:33)
+  2 |
+  3 | function* generator() {
+> 4 |     console.log("Sent", function.sent);
+    |                                 ^
+  5 |     console.log("Yield", yield);
+  6 | }
+  7 |"
+`;
+
 exports[`import-assertions-dynamic.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-ts", "babel-flow"]
@@ -1391,6 +1467,15 @@ exports[`module-blocks.js format[oxc] 1`] = `
   4 | };"
 `;
 
+exports[`module-blocks.js format[yuku] 1`] = `
+"Expected a semicolon or an implicit semicolon after a statement, but found '{' (1:16)
+> 1 | let m = module {
+    |                ^
+  2 |   export let m = 2;
+  3 |   export let n = 3;
+  4 | };"
+`;
+
 exports[`module-string-names.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-ts", "babel-flow"]
@@ -1754,6 +1839,13 @@ exports[`optional-chaining-assignment.js format[oxc] 1`] = `
   2 |"
 `;
 
+exports[`optional-chaining-assignment.js format[yuku] 1`] = `
+"Optional chaining is not allowed in assignment pattern (1:1)
+> 1 | maybeAnObj?.prop = theValue;
+    | ^^^^^^^^^^^^^^^^
+  2 |"
+`;
+
 exports[`partial-application.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-ts", "babel-flow"]
@@ -1854,6 +1946,17 @@ exports[`partial-application.js format[oxc] 1`] = `
   8 | const addTen = add(?, 10); // apply from the right"
 `;
 
+exports[`partial-application.js format[yuku] 1`] = `
+"Unexpected token '?' (5:23)
+  3 | function add(x, y) { return x + y; }
+  4 |
+> 5 | const addOne = add(1, ?); // apply from the left
+    |                       ^
+  6 | addOne(2); // 3
+  7 |
+  8 | const addTen = add(?, 10); // apply from the right"
+`;
+
 exports[`pipeline-operator-fsharp.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-ts", "babel-flow"]
@@ -1975,6 +2078,17 @@ exports[`pipeline-operator-fsharp.js format[oxc] 1`] = `
   8 |   |> x => x + '!'"
 `;
 
+exports[`pipeline-operator-fsharp.js format[yuku] 1`] = `
+"Unexpected token '>' (5:4)
+  3 |
+  4 | promise
+> 5 |   |> await
+    |    ^
+  6 |   |> x => doubleSay(x, ', ')
+  7 |   |> capitalize
+  8 |   |> x => x + '!'"
+`;
+
 exports[`pipeline-operator-hack.cjs format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-ts", "babel-flow"]
@@ -2047,6 +2161,17 @@ exports[`pipeline-operator-hack.cjs format[oxc] 1`] = `
   8 | // (The % token isn't final; it might instead be @ or ? or #.)"
 `;
 
+exports[`pipeline-operator-hack.cjs format[yuku] 1`] = `
+"Unexpected token '>' (5:3)
+  3 |
+  4 | return list
+> 5 |  |> take(prefix.length, %)
+    |   ^
+  6 |  |> equals(%, prefix);
+  7 |
+  8 | // (The % token isn't final; it might instead be @ or ? or #.)"
+`;
+
 exports[`pipeline-operator-minimal.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-ts", "babel-flow"]
@@ -2126,6 +2251,17 @@ exports[`pipeline-operator-minimal.js format[oxc] 1`] = `
   11 |"
 `;
 
+exports[`pipeline-operator-minimal.js format[yuku] 1`] = `
+"Unexpected token '>' (8:4)
+   6 |
+   7 | let result = "hello"
+>  8 |   |> doubleSay
+     |    ^
+   9 |   |> capitalize
+  10 |   |> exclaim;
+  11 |"
+`;
+
 exports[`private-fields-in-in.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-ts", "babel-flow"]
@@ -2433,6 +2569,17 @@ exports[`throw-expressions.js format[oxc] 1`] = `
   6 |"
 `;
 
+exports[`throw-expressions.js format[yuku] 1`] = `
+"'throw' is reserved and cannot be used as an identifier (3:23)
+  1 | // https://babeljs.io/docs/babel-plugin-proposal-throw-expressions
+  2 |
+> 3 | function test(param = throw new Error('required!')) {
+    |                       ^^^^^
+  4 |   const test = param === true || throw new Error('Falsy!');
+  5 | }
+  6 |"
+`;
+
 exports[`typescript.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-ts", "babel-flow"]
@@ -2509,6 +2656,15 @@ exports[`typescript.js format[oxc] 1`] = `
   4 |"
 `;
 
+exports[`typescript.js format[yuku] 1`] = `
+"'const' declarations must be initialized (3:7)
+  1 | // https://babeljs.io/docs/babel-preset-typescript
+  2 |
+> 3 | const x: number = 0;
+    |       ^
+  4 |"
+`;
+
 exports[`v8intrinsic.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-ts", "babel-flow"]
@@ -2615,3 +2771,14 @@ exports[`v8intrinsic.js format[oxc] 1`] = `
   5 |
   6 | // Invalid code https://github.com/JLHwung/babel/blob/c1a3cbfd65e08b7013fd6f8c62add8cb10b4b169/packages/babel-parser/test/fixtures/v8intrinsic/_errors/in-bind-expression/options.json"
 `;
+
+exports[`v8intrinsic.js format[yuku] 1`] = `
+"Unexpected token '%' (3:1)
+  1 | // https://github.com/babel/babel/pull/10148
+  2 |
+> 3 | %DebugPrint(foo);
+    | ^
+  4 |
+  5 |
+  6 | // Invalid code https://github.com/JLHwung/babel/blob/c1a3cbfd65e08b7013fd6f8c62add8cb10b4b169/packages/babel-parser/test/fixtures/v8intrinsic/_errors/in-bind-expression/options.json"
+`;

tests/format/js/babel-plugins/format.test.js

@@ -111,6 +111,25 @@ runFormatTest(import.meta, ["babel", "babel-ts", "babel-flow"], {
       "v8intrinsic.js",
       "discard-binding.js",
     ],
+    yuku: [
+      "async-do-expressions.js",
+      "destructuring-private.js",
+      "do-expressions.js",
+      "export-default-from.js",
+      "flow.js",
+      "function-bind.js",
+      "function-sent.js",
+      "module-blocks.js",
+      "optional-chaining-assignment.js",
+      "partial-application.js",
+      "pipeline-operator-fsharp.js",
+      "pipeline-operator-hack.cjs",
+      "pipeline-operator-minimal.js",
+      "throw-expressions.js",
+      "typescript.js",
+      "v8intrinsic.js",
+      "discard-binding.js",
+    ],
     babel: ["flow.js", "typescript.js"],
     __babel_estree: ["flow.js", "typescript.js"],
   },

tests/format/js/bind-expressions/__snapshots__/format.test.js.snap

@@ -63,6 +63,16 @@ exports[`await.js - {"semi":false} format[oxc] 1`] = `
   5 |"
 `;
 
+exports[`await.js - {"semi":false} format[yuku] 1`] = `
+"Expected a semicolon or an implicit semicolon after a statement, but found ':' (3:27)
+  1 | const doBothThings = async () => {
+  2 |     const request = doAsyncThing();
+> 3 |     return (await request)::doSyncThing();
+    |                           ^
+  4 | };
+  5 |"
+`;
+
 exports[`await.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -125,6 +135,16 @@ exports[`await.js format[oxc] 1`] = `
   5 |"
 `;
 
+exports[`await.js format[yuku] 1`] = `
+"Expected a semicolon or an implicit semicolon after a statement, but found ':' (3:27)
+  1 | const doBothThings = async () => {
+  2 |     const request = doAsyncThing();
+> 3 |     return (await request)::doSyncThing();
+    |                           ^
+  4 | };
+  5 |"
+`;
+
 exports[`bind_parens.js - {"semi":false} format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -252,6 +272,15 @@ exports[`bind_parens.js - {"semi":false} format[oxc] 1`] = `
   4 | (void 0)::func();"
 `;
 
+exports[`bind_parens.js - {"semi":false} format[yuku] 1`] = `
+"Expected a semicolon or an implicit semicolon after a statement, but found ':' (1:9)
+> 1 | (a || b)::c;
+    |         ^
+  2 | a || (b::c);
+  3 | ::obj.prop;
+  4 | (void 0)::func();"
+`;
+
 exports[`bind_parens.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -378,6 +407,15 @@ exports[`bind_parens.js format[oxc] 1`] = `
   4 | (void 0)::func();"
 `;
 
+exports[`bind_parens.js format[yuku] 1`] = `
+"Expected a semicolon or an implicit semicolon after a statement, but found ':' (1:9)
+> 1 | (a || b)::c;
+    |         ^
+  2 | a || (b::c);
+  3 | ::obj.prop;
+  4 | (void 0)::func();"
+`;
+
 exports[`long_name_method.js - {"semi":false} format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -455,6 +493,17 @@ exports[`long_name_method.js - {"semi":false} format[oxc] 1`] = `
   6 |   testLongNameMethodAndSomethingElseLallala() {"
 `;
 
+exports[`long_name_method.js - {"semi":false} format[yuku] 1`] = `
+"Unexpected token ':' (3:54)
+  1 | class X {
+  2 |   constructor() {
+> 3 |     this.testLongNameMethodAndSomethingElseLallala = ::this.testLongNameMethodAndSomethingElseLallala;
+    |                                                      ^
+  4 |   }
+  5 |   
+  6 |   testLongNameMethodAndSomethingElseLallala() {"
+`;
+
 exports[`long_name_method.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -531,6 +580,17 @@ exports[`long_name_method.js format[oxc] 1`] = `
   6 |   testLongNameMethodAndSomethingElseLallala() {"
 `;
 
+exports[`long_name_method.js format[yuku] 1`] = `
+"Unexpected token ':' (3:54)
+  1 | class X {
+  2 |   constructor() {
+> 3 |     this.testLongNameMethodAndSomethingElseLallala = ::this.testLongNameMethodAndSomethingElseLallala;
+    |                                                      ^
+  4 |   }
+  5 |   
+  6 |   testLongNameMethodAndSomethingElseLallala() {"
+`;
+
 exports[`method_chain.js - {"semi":false} format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -624,6 +684,17 @@ exports[`method_chain.js - {"semi":false} format[oxc] 1`] = `
   13 |                 ::take(1)"
 `;
 
+exports[`method_chain.js - {"semi":false} format[yuku] 1`] = `
+"Unexpected token ':' (10:9)
+   8 | function test(observable) {
+   9 |     return observable
+> 10 |         ::filter(data => data.someTest)
+     |         ^
+  11 |         ::throttle(() =>
+  12 |             interval(10)
+  13 |                 ::take(1)"
+`;
+
 exports[`method_chain.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -716,6 +787,17 @@ exports[`method_chain.js format[oxc] 1`] = `
   13 |                 ::take(1)"
 `;
 
+exports[`method_chain.js format[yuku] 1`] = `
+"Unexpected token ':' (10:9)
+   8 | function test(observable) {
+   9 |     return observable
+> 10 |         ::filter(data => data.someTest)
+     |         ^
+  11 |         ::throttle(() =>
+  12 |             interval(10)
+  13 |                 ::take(1)"
+`;
+
 exports[`short_name_method.js - {"semi":false} format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -792,6 +874,17 @@ exports[`short_name_method.js - {"semi":false} format[oxc] 1`] = `
   6 |   shortMethod() {"
 `;
 
+exports[`short_name_method.js - {"semi":false} format[yuku] 1`] = `
+"Unexpected token ':' (3:24)
+  1 | class X {
+  2 |   constructor() {
+> 3 |     this.shortMethod = ::this.shortMethod;
+    |                        ^
+  4 |   }
+  5 |   
+  6 |   shortMethod() {"
+`;
+
 exports[`short_name_method.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -867,6 +960,17 @@ exports[`short_name_method.js format[oxc] 1`] = `
   6 |   shortMethod() {"
 `;
 
+exports[`short_name_method.js format[yuku] 1`] = `
+"Unexpected token ':' (3:24)
+  1 | class X {
+  2 |   constructor() {
+> 3 |     this.shortMethod = ::this.shortMethod;
+    |                        ^
+  4 |   }
+  5 |   
+  6 |   shortMethod() {"
+`;
+
 exports[`unary.js - {"semi":false} format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -946,6 +1050,15 @@ exports[`unary.js - {"semi":false} format[oxc] 1`] = `
   4 | !("
 `;
 
+exports[`unary.js - {"semi":false} format[yuku] 1`] = `
+"Expected a semicolon or an implicit semicolon after a statement, but found ':' (1:3)
+> 1 | !x::y;
+    |   ^
+  2 | !(x::y /* foo */);
+  3 | !(/* foo */ x::y);
+  4 | !("
+`;
+
 exports[`unary.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -1023,3 +1136,12 @@ exports[`unary.js format[oxc] 1`] = `
   3 | !(/* foo */ x::y);
   4 | !("
 `;
+
+exports[`unary.js format[yuku] 1`] = `
+"Expected a semicolon or an implicit semicolon after a statement, but found ':' (1:3)
+> 1 | !x::y;
+    |   ^
+  2 | !(x::y /* foo */);
+  3 | !(/* foo */ x::y);
+  4 | !("
+`;

tests/format/js/bind-expressions/format.test.js

@@ -4,6 +4,7 @@ const errors = {
   meriyah: true,
   oxc: true,
   "oxc-ts": true,
+  yuku: true,
 };
 
 runFormatTest(import.meta, ["babel"], { errors });

tests/format/js/call/invalid/__snapshots__/format.test.js.snap

@@ -58,3 +58,12 @@ exports[`null-arguments-item.js format[oxc] 1`] = `
   3 | foo("a",
   4 |     //1"
 `;
+
+exports[`null-arguments-item.js format[yuku] 1`] = `
+"Unexpected token ',' (1:11)
+> 1 | foor('a', , 'b');
+    |           ^
+  2 | foo('looooooooooooooooooooooooooooooooooooooooooooooong', , 'looooooooooooooooooooooooooooooooooooooooooooooong');
+  3 | foo("a",
+  4 |     //1"
+`;

tests/format/js/call/invalid/format.test.js

@@ -7,5 +7,6 @@ runFormatTest(import.meta, ["babel"], {
     meriyah: true,
     oxc: true,
     "oxc-ts": true,
+    yuku: true,
   },
 });

tests/format/js/comments-pipeline-own-line/__snapshots__/format.test.js.snap

@@ -133,3 +133,14 @@ exports[`pipeline_own_line.js format[oxc] 1`] = `
   6 |
   7 | bifornCringerMoshedPerplexSawder("
 `;
+
+exports[`pipeline_own_line.js format[yuku] 1`] = `
+"Unexpected token '>' (4:3)
+  2 | 	0
+  3 | 	// Comment
+> 4 | 	|> x
+    | 	 ^
+  5 | }
+  6 |
+  7 | bifornCringerMoshedPerplexSawder("
+`;

tests/format/js/comments-pipeline-own-line/format.test.js

@@ -5,5 +5,6 @@ runFormatTest(import.meta, ["babel"], {
     meriyah: true,
     oxc: true,
     "oxc-ts": true,
+    yuku: true,
   },
 });

tests/format/js/deferred-import-evaluation/__snapshots__/format.test.js.snap

@@ -74,6 +74,13 @@ exports[`dynamic-import-attributes-expression.js format[meriyah] 1`] = `
 Cause: [1:7-1:12]: The only valid meta property for import is 'import.meta'"
 `;
 
+exports[`dynamic-import-attributes-expression.js format[yuku] 1`] = `
+"Expected ')' after import(), but found ',' (1:17)
+> 1 | import.defer("x", { with: { attr: "val" } });
+    |                 ^
+  2 |"
+`;
+
 exports[`import-defer.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "typescript"]
@@ -223,6 +230,13 @@ exports[`no-default.js format[oxc-ts] 1`] = `
   2 |"
 `;
 
+exports[`no-default.js format[yuku] 1`] = `
+"Expected 'from' after import clause, but found 'x' (1:14)
+> 1 | import defer x from "x";
+    |              ^
+  2 |"
+`;
+
 exports[`no-named.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "typescript"]
@@ -297,3 +311,10 @@ exports[`no-named.js format[oxc-ts] 1`] = `
     |        ^^^^^
   2 |"
 `;
+
+exports[`no-named.js format[yuku] 1`] = `
+"Expected 'from' after import clause, but found '{' (1:14)
+> 1 | import defer { x } from "x";
+    |              ^
+  2 |"
+`;

tests/format/js/deferred-import-evaluation/format.test.js

@@ -13,6 +13,7 @@ runFormatTest(import.meta, ["babel", "typescript"], {
     meriyah: [...importDeferTests, ...invalidSyntaxTests],
     oxc: invalidSyntaxTests,
     "oxc-ts": invalidSyntaxTests,
+    yuku: ["dynamic-import-attributes-expression.js", ...invalidSyntaxTests],
     babel: invalidSyntaxTests,
     "babel-ts": invalidSyntaxTests,
     __babel_estree: invalidSyntaxTests,

tests/format/js/destructuring-private-fields/__snapshots__/format.test.js.snap

@@ -62,6 +62,16 @@ exports[`arrow-params.js format[oxc] 1`] = `
   5 |"
 `;
 
+exports[`arrow-params.js format[yuku] 1`] = `
+"Unexpected token '#x' as property key (3:11)
+  1 | class C {
+  2 |   #x = 1;
+> 3 |   #p = ({ #x: x }) => {}
+    |           ^^
+  4 | }
+  5 |"
+`;
+
 exports[`assignment.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-flow", "babel-ts"]
@@ -134,6 +144,17 @@ exports[`assignment.js format[oxc] 1`] = `
   8 |"
 `;
 
+exports[`assignment.js format[yuku] 1`] = `
+"Unexpected token '#x' as property key (5:8)
+  3 |   m() {
+  4 |     let x;
+> 5 |     ({ #x: x } = this);
+    |        ^^
+  6 |   }
+  7 | }
+  8 |"
+`;
+
 exports[`async-arrow-params.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-flow", "babel-ts"]
@@ -196,6 +217,16 @@ exports[`async-arrow-params.js format[oxc] 1`] = `
   5 |"
 `;
 
+exports[`async-arrow-params.js format[yuku] 1`] = `
+"Unexpected token '#x' as property key (3:17)
+  1 | class C {
+  2 |   #x = 1;
+> 3 |   #p = async ({ #x: x }) => {}
+    |                 ^^
+  4 | }
+  5 |"
+`;
+
 exports[`bindings.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-flow", "babel-ts"]
@@ -266,6 +297,17 @@ exports[`bindings.js format[oxc] 1`] = `
   7 |"
 `;
 
+exports[`bindings.js format[yuku] 1`] = `
+"Unexpected token '#x' as property key (4:12)
+  2 |   #x = 1;
+  3 |   m() {
+> 4 |     const {#x: x} = this;
+    |            ^^
+  5 |   }
+  6 | }
+  7 |"
+`;
+
 exports[`for-lhs.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-flow", "babel-ts"]
@@ -338,6 +380,17 @@ exports[`for-lhs.js format[oxc] 1`] = `
   8 |"
 `;
 
+exports[`for-lhs.js format[yuku] 1`] = `
+"Unexpected token '#x' as property key (5:11)
+  3 |   m() {
+  4 |     let x;
+> 5 |     for ({#x: x} of [this]);
+    |           ^^
+  6 |   }
+  7 | }
+  8 |"
+`;
+
 exports[`nested-bindings.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-flow", "babel-ts"]
@@ -413,6 +466,17 @@ exports[`nested-bindings.js format[oxc] 1`] = `
   7 |"
 `;
 
+exports[`nested-bindings.js format[yuku] 1`] = `
+"Unexpected token '#x' as property key (4:17)
+  2 |   #x = 1;
+  3 |   m() {
+> 4 |     const {x: { #x: [x] }, y: [...{ #x: y }]} = this;
+    |                 ^^
+  5 |   }
+  6 | }
+  7 |"
+`;
+
 exports[`valid-multiple-bindings.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "babel-flow", "babel-ts"]
@@ -482,3 +546,14 @@ exports[`valid-multiple-bindings.js format[oxc] 1`] = `
   6 | }
   7 |"
 `;
+
+exports[`valid-multiple-bindings.js format[yuku] 1`] = `
+"Unexpected token '#x' as property key (4:12)
+  2 |   #x = 1;
+  3 |   m() {
+> 4 |     const {#x: x1, #x: x2 = x1 } = this;
+    |            ^^
+  5 |   }
+  6 | }
+  7 |"
+`;

tests/format/js/destructuring-private-fields/format.test.js

@@ -5,5 +5,6 @@ runFormatTest(import.meta, ["babel", "babel-flow", "babel-ts"], {
     meriyah: true,
     oxc: true,
     "oxc-ts": true,
+    yuku: true,
   },
 });

tests/format/js/discard-binding/__snapshots__/format.test.js.snap

@@ -180,6 +180,17 @@ exports[`array-pattern.js format[typescript] 1`] = `
 Cause: Array element destructuring pattern expected."
 `;
 
+exports[`array-pattern.js format[yuku] 1`] = `
+"Unexpected token ',' (3:16)
+  1 | {
+  2 |   // destructuring binding
+> 3 |   const [, void, ] = value;
+    |                ^
+  4 | }
+  5 | {
+  6 |   // for-of destructuring binding"
+`;
+
 exports[`basic.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -285,6 +296,15 @@ exports[`basic.js format[typescript] 1`] = `
 Cause: Array element destructuring pattern expected."
 `;
 
+exports[`basic.js format[yuku] 1`] = `
+"Unexpected token ']' (1:12)
+> 1 | const [void] = [,void] = [void,] = [];
+    |            ^
+  2 |
+  3 | function f(void, { p: void }, [ void ]) {}
+  4 |"
+`;
+
 exports[`discard-binding-arrow-params.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -362,6 +382,13 @@ exports[`discard-binding-arrow-params.js format[typescript] 1`] = `
 Cause: Expression expected."
 `;
 
+exports[`discard-binding-arrow-params.js format[yuku] 1`] = `
+"Unexpected token ')' (1:6)
+> 1 | (void) => {}
+    |      ^
+  2 |"
+`;
+
 exports[`discard-binding-assignment.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -439,6 +466,13 @@ exports[`discard-binding-assignment.js format[typescript] 1`] = `
 Cause: Expression expected."
 `;
 
+exports[`discard-binding-assignment.js format[yuku] 1`] = `
+"Unexpected token ']' (1:7)
+> 1 | ([void] = []);
+    |       ^
+  2 |"
+`;
+
 exports[`discard-binding-async-arrow-params.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -516,6 +550,13 @@ exports[`discard-binding-async-arrow-params.js format[typescript] 1`] = `
 Cause: Expression expected."
 `;
 
+exports[`discard-binding-async-arrow-params.js format[yuku] 1`] = `
+"Unexpected token ')' (1:12)
+> 1 | async (void) => {}
+    |            ^
+  2 |"
+`;
+
 exports[`discard-binding-bindings.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -593,6 +634,13 @@ exports[`discard-binding-bindings.js format[typescript] 1`] = `
 Cause: Identifier expected. 'void' is a reserved word that cannot be used here."
 `;
 
+exports[`discard-binding-bindings.js format[yuku] 1`] = `
+"Unexpected token '}' (1:17)
+> 1 | const { p: void } = {};
+    |                 ^
+  2 |"
+`;
+
 exports[`discard-binding-for-await-using-binding.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -690,6 +738,15 @@ exports[`discard-binding-for-await-using-binding.js format[typescript] 1`] = `
 Cause: ';' expected."
 `;
 
+exports[`discard-binding-for-await-using-binding.js format[yuku] 1`] = `
+"'void' is reserved and cannot be used as a binding identifier (2:19)
+  1 | async () => {
+> 2 |   for(await using void of []);
+    |                   ^^^^
+  3 | }
+  4 |"
+`;
+
 exports[`discard-binding-for-bindings.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -767,6 +824,13 @@ exports[`discard-binding-for-bindings.js format[typescript] 1`] = `
 Cause: Identifier expected. 'void' is a reserved word that cannot be used here."
 `;
 
+exports[`discard-binding-for-bindings.js format[yuku] 1`] = `
+"Unexpected token '}' (1:21)
+> 1 | for(const { p: void } of []);
+    |                     ^
+  2 |"
+`;
+
 exports[`discard-binding-for-lhs.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -844,6 +908,13 @@ exports[`discard-binding-for-lhs.js format[typescript] 1`] = `
 Cause: Expression expected."
 `;
 
+exports[`discard-binding-for-lhs.js format[yuku] 1`] = `
+"Unexpected token '}' (1:15)
+> 1 | for({ p: void } of []);
+    |               ^
+  2 |"
+`;
+
 exports[`discard-binding-for-using-binding.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -937,6 +1008,15 @@ exports[`discard-binding-for-using-binding.js format[typescript] 1`] = `
 Cause: ';' expected."
 `;
 
+exports[`discard-binding-for-using-binding.js format[yuku] 1`] = `
+"'void' is reserved and cannot be used as a binding identifier (2:13)
+  1 | {
+> 2 |   for(using void of []);
+    |             ^^^^
+  3 | }
+  4 |"
+`;
+
 exports[`function-parameter.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -1086,6 +1166,17 @@ exports[`function-parameter.js format[typescript] 1`] = `
 Cause: Identifier expected. 'void' is a reserved word that cannot be used here."
 `;
 
+exports[`function-parameter.js format[yuku] 1`] = `
+"'void' is reserved and cannot be used as a binding identifier (3:14)
+  1 | {
+  2 |   // function parameter
+> 3 |   function f(void) {}
+    |              ^^^^
+  4 | }
+  5 | {
+  6 |   // arrow function parameter"
+`;
+
 exports[`object-pattern.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -1284,6 +1375,17 @@ exports[`object-pattern.js format[typescript] 1`] = `
 Cause: Identifier expected. 'void' is a reserved word that cannot be used here."
 `;
 
+exports[`object-pattern.js format[yuku] 1`] = `
+"Unexpected token '}' (3:22)
+  1 | {
+  2 |   // destructuring binding
+> 3 |   const { void: void } = value;
+    |                      ^
+  4 | }
+  5 | {
+  6 |   // for-of destructuring binding"
+`;
+
 exports[`unary-expression-void.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -1425,6 +1527,17 @@ exports[`unary-expression-void.js format[typescript] 1`] = `
 Cause: Expression expected."
 `;
 
+exports[`unary-expression-void.js format[yuku] 1`] = `
+"Unexpected token ']' (4:10)
+  2 | void [
+  3 |   // pattern
+> 4 |   [ void ] = [{
+    |          ^
+  5 |     // expr
+  6 |     [ void [] ]:
+  7 |     // pattern"
+`;
+
 exports[`using.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -1536,6 +1649,16 @@ exports[`using.js format[typescript] 1`] = `
 Cause: Unexpected keyword or identifier."
 `;
 
+exports[`using.js format[yuku] 1`] = `
+"'void' is reserved and cannot be used as a binding identifier (2:9)
+  1 | {
+> 2 |   using void = f();
+    |         ^^^^
+  3 | }
+  4 | async (void) => {
+  5 |   await using void = f();"
+`;
+
 exports[`using-variable-declarator.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -1714,3 +1837,14 @@ exports[`using-variable-declarator.js format[typescript] 1`] = `
   6 |   // using 2 declarators
 Cause: Unexpected keyword or identifier."
 `;
+
+exports[`using-variable-declarator.js format[yuku] 1`] = `
+"'void' is reserved and cannot be used as a binding identifier (3:9)
+  1 | {
+  2 |   // using 1 declarator
+> 3 |   using void = f();
+    |         ^^^^
+  4 | }
+  5 | {
+  6 |   // using 2 declarators"
+`;

tests/format/js/discard-binding/format.test.js

@@ -7,6 +7,7 @@ runFormatTest(import.meta, ["babel", "flow", "typescript"], {
     meriyah: true,
     oxc: true,
     "oxc-ts": true,
+    yuku: true,
     hermes: true,
   },
 });

tests/format/js/do/__snapshots__/format.test.js.snap

@@ -132,6 +132,17 @@ exports[`call-arguments.js format[oxc] 1`] = `
   6 |       "unreachable""
 `;
 
+exports[`call-arguments.js format[yuku] 1`] = `
+"'do' is reserved and cannot be used as an identifier (3:3)
+  1 | // from https://github.com/babel/babel/pull/13122/
+  2 | expect(
+> 3 |   do {
+    |   ^^
+  4 |     var bar = "foo";
+  5 |     if (!bar) throw new Error(
+  6 |       "unreachable""
+`;
+
 exports[`do.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -328,3 +339,14 @@ exports[`do.js format[oxc] 1`] = `
   5 |       else if(env === 'development') 'http://localhost:4000';
   6 |     }"
 `;
+
+exports[`do.js format[yuku] 1`] = `
+"'do' is reserved and cannot be used as an identifier (3:5)
+  1 | const envSpecific = {
+  2 |   domain:
+> 3 |     do {
+    |     ^^
+  4 |       if(env === 'production') 'https://abc.mno.com/';
+  5 |       else if(env === 'development') 'http://localhost:4000';
+  6 |     }"
+`;

tests/format/js/do/format.test.js

@@ -5,5 +5,6 @@ runFormatTest(import.meta, ["babel"], {
     meriyah: true,
     oxc: true,
     "oxc-ts": true,
+    yuku: true,
   },
 });

tests/format/js/explicit-resource-management/__snapshots__/format.test.js.snap

@@ -235,6 +235,16 @@ async function f() {
 ================================================================================
 `;
 
+exports[`valid-await-expr-using.js format[yuku] 1`] = `
+"Expected a semicolon or an implicit semicolon after a statement, but found '+' (3:17)
+  1 | async function f() {
+  2 |   await using[x];
+> 3 |   await using.x + await using(x) ? await using?.x : await using\`x\`;
+    |                 ^
+  4 | }
+  5 |"
+`;
+
 exports[`valid-await-expr-using-in.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -264,6 +274,15 @@ Cause: 'identifier' expected in declaration (2:14)
   ~~~~~~~~~~~~^"
 `;
 
+exports[`valid-await-expr-using-in.js format[yuku] 1`] = `
+"'in' is reserved and cannot be used as a binding identifier (2:15)
+  1 | async function f() {
+> 2 |   await using in foo;
+    |               ^^
+  3 | }
+  4 |"
+`;
+
 exports[`valid-await-expr-using-instanceof.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -293,6 +312,15 @@ Cause: 'identifier' expected in declaration (2:14)
   ~~~~~~~~~~~~^"
 `;
 
+exports[`valid-await-expr-using-instanceof.js format[yuku] 1`] = `
+"'instanceof' is reserved and cannot be used as a binding identifier (2:15)
+  1 | async function f() {
+> 2 |   await using instanceof foo;
+    |               ^^^^^^^^^^
+  3 | }
+  4 |"
+`;
+
 exports[`valid-await-using-asi-assignment.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -761,6 +789,15 @@ exports[`valid-module-block-top-level-await-using-binding.js format[typescript]
 Cause: ',' expected."
 `;
 
+exports[`valid-module-block-top-level-await-using-binding.js format[yuku] 1`] = `
+"Expected a semicolon or an implicit semicolon after a statement, but found '{' (1:18)
+> 1 | const m = module {
+    |                  ^
+  2 |   await using foo = bar();
+  3 | }
+  4 |"
+`;
+
 exports[`valid-module-block-top-level-using-binding.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -858,6 +895,15 @@ exports[`valid-module-block-top-level-using-binding.js format[typescript] 1`] =
 Cause: Namespace must be given a name."
 `;
 
+exports[`valid-module-block-top-level-using-binding.js format[yuku] 1`] = `
+"Expected a semicolon or an implicit semicolon after a statement, but found '{' (1:8)
+> 1 | module {
+    |        ^
+  2 |   using foo = bar();
+  3 | }
+  4 |"
+`;
+
 exports[`valid-using-as-identifier-computed-member.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -946,6 +992,15 @@ exports[`valid-using-as-identifier-for-in.js format[hermes] 1`] = `
 Cause: Failed to parse source"
 `;
 
+exports[`valid-using-as-identifier-for-in.js format[yuku] 1`] = `
+"Unexpected token '\`\`' in binding pattern (4:11)
+  2 | for (using.foo in []);
+  3 | for (using().foo in []);
+> 4 | for (using\`\`.foo in []);
+    |           ^^
+  5 |"
+`;
+
 exports[`valid-using-as-identifier-for-init.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -961,6 +1016,15 @@ for (using; (reader = getReader()););
 ================================================================================
 `;
 
+exports[`valid-using-as-identifier-for-init.js format[yuku] 1`] = `
+"Unexpected token ';' in binding pattern (2:8)
+  1 | for (
+> 2 |   using;
+    |        ^
+  3 |   reader = getReader(););
+  4 |"
+`;
+
 exports[`valid-using-as-identifier-for-of.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -980,6 +1044,15 @@ for (using\`\`.foo of of);
 ================================================================================
 `;
 
+exports[`valid-using-as-identifier-for-of.js format[yuku] 1`] = `
+"Unexpected token '\`\`' in binding pattern (4:11)
+  2 | for (using.foo of of);
+  3 | for (using().foo of of);
+> 4 | for (using\`\`.foo of of);
+    |           ^^
+  5 |"
+`;
+
 exports[`valid-using-as-identifier-in.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]
@@ -1003,6 +1076,13 @@ using in using instanceof using;
 ~~~~~~^"
 `;
 
+exports[`valid-using-as-identifier-in.js format[yuku] 1`] = `
+"'in' is reserved and cannot be used as a binding identifier (1:7)
+> 1 | using in using instanceof using;
+    |       ^^
+  2 |"
+`;
+
 exports[`valid-using-binding-basic.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]

tests/format/js/explicit-resource-management/format.test.js

@@ -94,5 +94,18 @@ runFormatTest(import.meta, ["babel", "flow", "typescript"], {
       "valid-module-block-top-level-using-binding.js",
       "valid-module-block-top-level-await-using-binding.js",
     ],
+    yuku: [
+      // "invalid-duplicate-using-bindings.js",
+      // "invalid-script-top-level-using-binding.js",
+      "valid-module-block-top-level-using-binding.js",
+      "valid-module-block-top-level-await-using-binding.js",
+      "valid-await-expr-using-in.js",
+      "valid-await-expr-using-instanceof.js",
+      "valid-await-expr-using.js",
+      "valid-using-as-identifier-for-in.js",
+      "valid-using-as-identifier-for-init.js",
+      "valid-using-as-identifier-for-of.js",
+      "valid-using-as-identifier-in.js",
+    ],
   },
 });

tests/format/js/export-default/escaped/__snapshots__/format.test.js.snap

@@ -62,3 +62,10 @@ exports[`default-escaped.js format[oxc] 1`] = `
 > 2 | export n\\u{63} from "async";
     |        ^^^^^^^"
 `;
+
+exports[`default-escaped.js format[yuku] 1`] = `
+"Expected declaration after 'export', but found 'n\\u{63}' (2:8)
+  1 | // export asyn\\u{63} from "async";
+> 2 | export n\\u{63} from "async";
+    |        ^^^^^^^"
+`;

tests/format/js/export-default/escaped/format.test.js

@@ -7,5 +7,6 @@ runFormatTest(import.meta, ["babel", "flow"], {
     hermes: true,
     oxc: true,
     "oxc-ts": true,
+    yuku: true,
   },
 });

tests/format/js/export-default/export-default-from/__snapshots__/format.test.js.snap

@@ -72,3 +72,13 @@ exports[`export.js format[oxc] 1`] = `
   4 | export c, { foo } from 'mod';
   5 | export * as d from 'mod';"
 `;
+
+exports[`export.js format[yuku] 1`] = `
+"Expected declaration after 'export', but found 'v' (2:8)
+  1 | export * as ns from 'mod';
+> 2 | export v from 'mod';
+    |        ^
+  3 | export a, * as b from 'mod';
+  4 | export c, { foo } from 'mod';
+  5 | export * as d from 'mod';"
+`;

tests/format/js/export-default/export-default-from/format.test.js

@@ -5,5 +5,6 @@ runFormatTest(import.meta, ["babel"], {
     meriyah: true,
     oxc: true,
     "oxc-ts": true,
+    yuku: true,
   },
 });

tests/format/js/for/__snapshots__/format.test.js.snap

@@ -917,6 +917,17 @@ exports[`for-in-with-initializer.js format[typescript] 1`] = `
 Cause: ',' expected."
 `;
 
+exports[`for-in-with-initializer.js format[yuku] 1`] = `
+"Expected ';' after for-loop init, but found ')' (4:33)
+  2 |
+  3 | for (var a = (b in c) in {});
+> 4 | for (var a = 1 || (b in c) in {});
+    |                                 ^
+  5 | for (var a = 1 + (2 || (b in c)) in {});
+  6 | for (var a = (() => b in c) in {});
+  7 | for (var a = 1 || (() => b in c) in {});"
+`;
+
 exports[`in.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]

tests/format/js/for/format.test.js

@@ -2,5 +2,6 @@ runFormatTest(import.meta, ["babel", "flow", "typescript"], {
   errors: {
     flow: ["parentheses.js", "for-in-with-initializer.js"],
     typescript: ["parentheses.js", "for-in-with-initializer.js"],
+    yuku: ["for-in-with-initializer.js"],
   },
 });

tests/format/js/identifier/parentheses/__snapshots__/format.test.js.snap

@@ -252,6 +252,15 @@ a[1] + (let[2] = 2)
 ================================================================================
 `;
 
+exports[`let.js - {"semi":false} format[yuku] 1`] = `
+"Unexpected token '.' in binding pattern (1:4)
+> 1 | let.a = 1;
+    |    ^
+  2 |
+  3 | let.a[0] = 1;
+  4 |"
+`;
+
 exports[`let.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "typescript"]
@@ -475,3 +484,12 @@ a[1] + (let[2] = 2);
 
 ================================================================================
 `;
+
+exports[`let.js format[yuku] 1`] = `
+"Unexpected token '.' in binding pattern (1:4)
+> 1 | let.a = 1;
+    |    ^
+  2 |
+  3 | let.a[0] = 1;
+  4 |"
+`;

tests/format/js/identifier/parentheses/format.test.js

@@ -1,8 +1,5 @@
-runFormatTest(import.meta, [
-  "babel",
-  //  "flow",
-  "typescript",
-]);
+const errors = { yuku: ["let.js"] };
+
 runFormatTest(
   import.meta,
   [
@@ -10,5 +7,14 @@ runFormatTest(
     //  "flow",
     "typescript",
   ],
-  { semi: false },
+  { errors },
+);
+runFormatTest(
+  import.meta,
+  [
+    "babel",
+    // "flow",
+    "typescript",
+  ],
+  { semi: false, errors },
 );

tests/format/js/import-assertions/__snapshots__/format.test.js.snap

@@ -2,7 +2,7 @@
 
 exports[`dynamic-import.js format 1`] = `
 ====================================options=====================================
-parsers: ["oxc", "typescript", "hermes"]
+parsers: ["oxc", "yuku", "typescript", "hermes"]
                                                       printWidth: 80 (default) |
 =====================================input======================================
 import("./foo.json", { assert: { type: "json" } });
@@ -15,7 +15,7 @@ import("./foo.json", { assert: { type: "json" } });
 
 exports[`empty.js format 1`] = `
 ====================================options=====================================
-parsers: ["oxc", "typescript", "hermes"]
+parsers: ["oxc", "yuku", "typescript", "hermes"]
                                                       printWidth: 80 (default) |
 =====================================input======================================
 export * as foo from "foo.json"
@@ -63,7 +63,7 @@ export * as bar from "bar.json" assert { }
 
 exports[`keyword-detect.js format 1`] = `
 ====================================options=====================================
-parsers: ["oxc", "typescript", "hermes"]
+parsers: ["oxc", "yuku", "typescript", "hermes"]
                                                       printWidth: 80 (default) |
 =====================================input======================================
 import "./test.json" /* with */ assert /* with */  { type: "json" }
@@ -108,7 +108,7 @@ import "./test.json" /* with */ assert /* with */  { type: "json" }
 
 exports[`multi-types.js format 1`] = `
 ====================================options=====================================
-parsers: ["oxc", "typescript", "hermes"]
+parsers: ["oxc", "yuku", "typescript", "hermes"]
                                                       printWidth: 80 (default) |
 =====================================input======================================
 import json from "./foo.json" assert { type: "json", type: "bar" };
@@ -139,7 +139,7 @@ import json from "./foo.json" assert { type: "json", type: "bar" };
 
 exports[`non-type.js format 1`] = `
 ====================================options=====================================
-parsers: ["oxc", "typescript", "hermes"]
+parsers: ["oxc", "yuku", "typescript", "hermes"]
                                                       printWidth: 80 (default) |
 =====================================input======================================
 import foo from "foo.json" assert { lazy: "true" };
@@ -170,7 +170,7 @@ import foo from "foo.json" assert { lazy: "true" };
 
 exports[`not-import-assertions.js format 1`] = `
 ====================================options=====================================
-parsers: ["oxc", "typescript", "hermes"]
+parsers: ["oxc", "yuku", "typescript", "hermes"]
                                                       printWidth: 80 (default) |
 =====================================input======================================
 import "x"
@@ -185,7 +185,7 @@ assert({ type: "json" });
 
 exports[`re-export.js format 1`] = `
 ====================================options=====================================
-parsers: ["oxc", "typescript", "hermes"]
+parsers: ["oxc", "yuku", "typescript", "hermes"]
                                                       printWidth: 80 (default) |
 =====================================input======================================
 export { default as foo2 } from "foo.json" assert { type: "json" };
@@ -224,7 +224,7 @@ export { default as foo2 } from "foo.json" assert { type: "json" };
 
 exports[`static-import.js format 1`] = `
 ====================================options=====================================
-parsers: ["oxc", "typescript", "hermes"]
+parsers: ["oxc", "yuku", "typescript", "hermes"]
                                                       printWidth: 80 (default) |
 =====================================input======================================
 import json from "./foo.json" assert { type: "json" };
@@ -255,7 +255,7 @@ import json from "./foo.json" assert { type: "json" };
 
 exports[`without-from.js format 1`] = `
 ====================================options=====================================
-parsers: ["oxc", "typescript", "hermes"]
+parsers: ["oxc", "yuku", "typescript", "hermes"]
                                                       printWidth: 80 (default) |
 =====================================input======================================
 import "foo" assert { type: "json" }

tests/format/js/import-assertions/format.test.js

@@ -1,4 +1,4 @@
-runFormatTest(import.meta, ["oxc", "typescript", "hermes"], {
+runFormatTest(import.meta, ["oxc", "yuku", "typescript", "hermes"], {
   errors: {
     "babel-ts": [
       "empty.js",

tests/format/js/module-blocks/__snapshots__/format.test.js.snap

@@ -71,6 +71,15 @@ exports[`comments.js format[oxc] 1`] = `
   4 |   export { foo }; /*A5*/"
 `;
 
+exports[`comments.js format[yuku] 1`] = `
+"Expected a semicolon or an implicit semicolon after a statement, but found '{' (1:32)
+> 1 | const m = /*A1*/ module /*A2*/ { /*A3*/
+    |                                ^
+  2 |   /*A4*/
+  3 |   export const foo = "foo";
+  4 |   export { foo }; /*A5*/"
+`;
+
 exports[`module-blocks.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -209,6 +218,15 @@ exports[`module-blocks.js format[oxc] 1`] = `
   4 |   #p() {"
 `;
 
+exports[`module-blocks.js format[yuku] 1`] = `
+"Expected a semicolon or an implicit semicolon after a statement, but found '{' (1:8)
+> 1 | module { await 3 };
+    |        ^
+  2 |
+  3 | class B {
+  4 |   #p() {"
+`;
+
 exports[`non-module-blocks.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -291,3 +309,12 @@ exports[`range.js format[oxc] 1`] = `
   3 |
   4 | foo(module { export let foo = "foo"; })"
 `;
+
+exports[`range.js format[yuku] 1`] = `
+"Expected a semicolon or an implicit semicolon after a statement, but found '{' (1:26)
+> 1 | let moduleBlock = module {  export let y = 1;
+    |                          ^
+  2 | };
+  3 |
+  4 | foo(module { export let foo = "foo"; })"
+`;

tests/format/js/module-blocks/format.test.js

@@ -4,6 +4,7 @@ const errors = {
   meriyah: ["module-blocks.js", "range.js", "comments.js"],
   oxc: ["module-blocks.js", "range.js", "comments.js"],
   "oxc-ts": ["module-blocks.js", "range.js", "comments.js"],
+  yuku: ["module-blocks.js", "range.js", "comments.js"],
 };
 
 runFormatTest(import.meta, ["babel"], { errors });

tests/format/js/module-blocks/quote-props/__snapshots__/format.test.js.snap

@@ -134,3 +134,12 @@ exports[`worker.js format[oxc] 1`] = `
   3 |     let mod = import(data);
   4 |     postMessage(mod.fn());"
 `;
+
+exports[`worker.js format[yuku] 1`] = `
+"Expected ')' after constructor arguments, but found '{' (1:28)
+> 1 | worker = new Worker(module {
+    |                            ^
+  2 |   onmessage = function({data}) {
+  3 |     let mod = import(data);
+  4 |     postMessage(mod.fn());"
+`;

tests/format/js/module-blocks/quote-props/format.test.js

@@ -5,5 +5,6 @@ runFormatTest(import.meta, ["babel"], {
     meriyah: ["worker.js"],
     oxc: ["worker.js"],
     "oxc-ts": ["worker.js"],
+    yuku: ["worker.js"],
   },
 });

tests/format/js/multiparser-invalid/__snapshots__/format.test.js.snap

@@ -166,3 +166,14 @@ exports[`text.js format[typescript] 1`] = `
   9 | foo = foo\`\\u{prettier}\${foo}pr\\u{0065}ttier\`;
 Cause: Hexadecimal digit expected."
 `;
+
+exports[`text.js format[yuku] 1`] = `
+"Bad escape sequence in untagged template literal (6:18)
+  4 | foo = markdown\`\\u{prettier}\\u{0065}\`;
+  5 | foo = css\`\\u{prettier}\\u{0065}\`;
+> 6 | foo = /* HTML */\`\\u{prettier}\\u{0065}\`;
+    |                  ^^^^^^^^^^^^^^^^^^^^
+  7 | foo = /* GraphQL */\`\\u{prettier}\\u{0065}\`;
+  8 |
+  9 | foo = foo\`\\u{prettier}\${foo}pr\\u{0065}ttier\`;"
+`;

tests/format/js/multiparser-invalid/format.test.js

@@ -8,5 +8,6 @@ runFormatTest(import.meta, ["babel", "flow", "typescript"], {
     meriyah: true,
     oxc: true,
     "oxc-ts": true,
+    yuku: true,
   },
 });

tests/format/js/no-semi-babylon-extensions/__snapshots__/format.test.js.snap

@@ -77,6 +77,16 @@ exports[`no-semi.js - {"semi":false} format[oxc] 1`] = `
   5 |   a = b;"
 `;
 
+exports[`no-semi.js - {"semi":false} format[yuku] 1`] = `
+"Unexpected token ':' (2:2)
+  1 | a
+> 2 | ;::b.c
+    |  ^
+  3 |
+  4 | class A {
+  5 |   a = b;"
+`;
+
 exports[`no-semi.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -152,3 +162,13 @@ exports[`no-semi.js format[oxc] 1`] = `
   4 | class A {
   5 |   a = b;"
 `;
+
+exports[`no-semi.js format[yuku] 1`] = `
+"Unexpected token ':' (2:2)
+  1 | a
+> 2 | ;::b.c
+    |  ^
+  3 |
+  4 | class A {
+  5 |   a = b;"
+`;

tests/format/js/no-semi-babylon-extensions/format.test.js

@@ -4,6 +4,7 @@ const errors = {
   meriyah: true,
   oxc: true,
   "oxc-ts": true,
+  yuku: true,
 };
 runFormatTest(import.meta, ["babel"], { errors });
 runFormatTest(import.meta, ["babel"], { semi: false, errors });

tests/format/js/objects/__snapshots__/format.test.js.snap

@@ -223,6 +223,17 @@ exports[`expression.js format[typescript] 1`] = `
 Cause: ')' expected."
 `;
 
+exports[`expression.js format[yuku] 1`] = `
+"Expected ',' or ')' in parenthesized expression, but found ':' (5:4)
+  3 | a = () => ({}).x;
+  4 | ({} && a, b);
+> 5 | ({}::b, 0);
+    |    ^
+  6 | ({}::b()\`\`[''].c++ && 0 ? 0 : 0, 0);
+  7 | ({}(), 0);
+  8 | ({} = 0);"
+`;
+
 exports[`getter-setter.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "typescript", "flow"]

tests/format/js/objects/format.test.js

@@ -6,6 +6,7 @@ runFormatTest(import.meta, ["babel", "typescript", "flow"], {
     meriyah: ["expression.js"],
     oxc: ["expression.js"],
     "oxc-ts": ["expression.js"],
+    yuku: ["expression.js"],
     flow: ["expression.js"],
     hermes: ["expression.js"],
   },

tests/format/js/optional-chaining-assignment/__snapshots__/format.test.js.snap

@@ -47,6 +47,13 @@ exports[`invalid-destructuring-arr.js format[oxc] 1`] = `
   2 |"
 `;
 
+exports[`invalid-destructuring-arr.js format[yuku] 1`] = `
+"Optional chaining is not allowed in assignment pattern (1:2)
+> 1 | [a?.b] = [];
+    |  ^^^^
+  2 |"
+`;
+
 exports[`invalid-destructuring-obj.js format[__babel_estree] 1`] = `
 "Invalid optional chaining in the left-hand side of object destructuring pattern. (1:10)
 > 1 | ({ prop: a?.b } = {});
@@ -94,6 +101,13 @@ exports[`invalid-destructuring-obj.js format[oxc] 1`] = `
   2 |"
 `;
 
+exports[`invalid-destructuring-obj.js format[yuku] 1`] = `
+"Optional chaining is not allowed in assignment pattern (1:10)
+> 1 | ({ prop: a?.b } = {});
+    |          ^^^^
+  2 |"
+`;
+
 exports[`invalid-fn-param.js format[__babel_estree] 1`] = `
 "Unexpected token, expected "," (1:13)
 > 1 | function f(a?.b) {}
@@ -141,6 +155,13 @@ exports[`invalid-fn-param.js format[oxc] 1`] = `
   2 |"
 `;
 
+exports[`invalid-fn-param.js format[yuku] 1`] = `
+"Expected ')' to close parameter list, but found '?.' (1:13)
+> 1 | function f(a?.b) {}
+    |             ^^
+  2 |"
+`;
+
 exports[`invalid-fn-param-arrow.js format[__babel_estree] 1`] = `
 "Invalid optional chaining in the left-hand side of function parameter list. (1:2)
 > 1 | (a?.b) => {}
@@ -188,6 +209,13 @@ exports[`invalid-fn-param-arrow.js format[oxc] 1`] = `
   2 |"
 `;
 
+exports[`invalid-fn-param-arrow.js format[yuku] 1`] = `
+"Optional chaining is not allowed in binding pattern (1:2)
+> 1 | (a?.b) => {}
+    |  ^^^^
+  2 |"
+`;
+
 exports[`invalid-fn-param-assign.js format[__babel_estree] 1`] = `
 "Unexpected token, expected "," (1:13)
 > 1 | function f(a?.b = c) {}
@@ -235,6 +263,13 @@ exports[`invalid-fn-param-assign.js format[oxc] 1`] = `
   2 |"
 `;
 
+exports[`invalid-fn-param-assign.js format[yuku] 1`] = `
+"Expected ')' to close parameter list, but found '?.' (1:13)
+> 1 | function f(a?.b = c) {}
+    |             ^^
+  2 |"
+`;
+
 exports[`invalid-for-await-of.js format[__babel_estree] 1`] = `
 "Invalid optional chaining in the left-hand side of for-of statement. (1:6)
 > 1 | for (a?.b of x);
@@ -282,6 +317,13 @@ exports[`invalid-for-await-of.js format[oxc] 1`] = `
   2 |"
 `;
 
+exports[`invalid-for-await-of.js format[yuku] 1`] = `
+"Optional chaining is not allowed in assignment pattern (1:6)
+> 1 | for (a?.b of x);
+    |      ^^^^
+  2 |"
+`;
+
 exports[`invalid-for-in.js format[__babel_estree] 1`] = `
 "Invalid optional chaining in the left-hand side of for-in statement. (1:6)
 > 1 | for (a?.b in x);
@@ -329,6 +371,13 @@ exports[`invalid-for-in.js format[oxc] 1`] = `
   2 |"
 `;
 
+exports[`invalid-for-in.js format[yuku] 1`] = `
+"Optional chaining is not allowed in assignment pattern (1:6)
+> 1 | for (a?.b in x);
+    |      ^^^^
+  2 |"
+`;
+
 exports[`invalid-for-of.js format[__babel_estree] 1`] = `
 "Invalid optional chaining in the left-hand side of for-of statement. (1:6)
 > 1 | for (a?.b of x);
@@ -376,6 +425,13 @@ exports[`invalid-for-of.js format[oxc] 1`] = `
   2 |"
 `;
 
+exports[`invalid-for-of.js format[yuku] 1`] = `
+"Optional chaining is not allowed in assignment pattern (1:6)
+> 1 | for (a?.b of x);
+    |      ^^^^
+  2 |"
+`;
+
 exports[`invalid-inc-postfix.js format[__babel_estree] 1`] = `
 "Invalid optional chaining in the left-hand side of postfix operation. (1:1)
 > 1 | a?.b++;
@@ -423,6 +479,13 @@ exports[`invalid-inc-postfix.js format[oxc] 1`] = `
   2 |"
 `;
 
+exports[`invalid-inc-postfix.js format[yuku] 1`] = `
+"Invalid operand for increment/decrement operator (1:1)
+> 1 | a?.b++;
+    | ^^^^
+  2 |"
+`;
+
 exports[`invalid-inc-prefix.js format[__babel_estree] 1`] = `
 "Invalid optional chaining in the left-hand side of prefix operation. (1:3)
 > 1 | ++a?.b;
@@ -470,6 +533,13 @@ exports[`invalid-inc-prefix.js format[oxc] 1`] = `
   2 |"
 `;
 
+exports[`invalid-inc-prefix.js format[yuku] 1`] = `
+"Invalid operand for increment/decrement operator (1:3)
+> 1 | ++a?.b;
+    |   ^^^^
+  2 |"
+`;
+
 exports[`valid-complex-case.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -520,6 +590,14 @@ exports[`valid-complex-case.js format[oxc] 1`] = `
   3 |"
 `;
 
+exports[`valid-complex-case.js format[yuku] 1`] = `
+"Unexpected token '?.' in binding pattern (1:4)
+> 1 | let?.()[a] =1;
+    |    ^^
+  2 | let?.[a] = 1;
+  3 |"
+`;
+
 exports[`valid-lhs-eq.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -556,6 +634,13 @@ exports[`valid-lhs-eq.js format[oxc] 1`] = `
   2 |"
 `;
 
+exports[`valid-lhs-eq.js format[yuku] 1`] = `
+"Optional chaining is not allowed in assignment pattern (1:1)
+> 1 | a?.b.c = d;
+    | ^^^^^^
+  2 |"
+`;
+
 exports[`valid-lhs-plus-eq.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -592,6 +677,13 @@ exports[`valid-lhs-plus-eq.js format[oxc] 1`] = `
   2 |"
 `;
 
+exports[`valid-lhs-plus-eq.js format[yuku] 1`] = `
+"Invalid assignment target (1:1)
+> 1 | a?.b.c += d;
+    | ^^^^^^
+  2 |"
+`;
+
 exports[`valid-parenthesized.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -635,3 +727,10 @@ exports[`valid-parenthesized.js format[oxc] 1`] = `
     |  ^^^^
   2 |"
 `;
+
+exports[`valid-parenthesized.js format[yuku] 1`] = `
+"Parenthesized expression in assignment pattern must be a simple assignment target (1:2)
+> 1 | (a?.b) = c;
+    |  ^^^^
+  2 |"
+`;

tests/format/js/optional-chaining-assignment/format.test.js

@@ -33,6 +33,7 @@ runFormatTest(import.meta, ["babel"], {
     ],
     oxc: [...optionalChainingAssignTests, ...invalidSyntaxTests],
     "oxc-ts": [...optionalChainingAssignTests, ...invalidSyntaxTests],
+    yuku: [...optionalChainingAssignTests, ...invalidSyntaxTests],
     babel: invalidSyntaxTests,
     __babel_estree: invalidSyntaxTests,
   },

tests/format/js/partial-application/__snapshots__/format.test.js.snap

@@ -67,3 +67,12 @@ exports[`test.js format[oxc] 1`] = `
   3 |
   4 | const addTen = add(?, 10); // apply from the right"
 `;
+
+exports[`test.js format[yuku] 1`] = `
+"Unexpected token '?' (1:23)
+> 1 | const addOne = add(1, ?); // apply from the left
+    |                       ^
+  2 | addOne(2); // 3
+  3 |
+  4 | const addTen = add(?, 10); // apply from the right"
+`;

tests/format/js/partial-application/format.test.js

@@ -5,5 +5,6 @@ runFormatTest(import.meta, ["babel"], {
     meriyah: true,
     oxc: true,
     "oxc-ts": true,
+    yuku: true,
   },
 });

tests/format/js/pipeline-operator/__snapshots__/format.test.js.snap

@@ -66,6 +66,16 @@ exports[`block-comments.js format[oxc] 1`] = `
   5 | |> kochabCooieGameOnOboleUnweave"
 `;
 
+exports[`block-comments.js format[yuku] 1`] = `
+"Unexpected token '>' (2:2)
+  1 | bifornCringerMoshedPerplexSawder
+> 2 | |> foo1
+    |  ^
+  3 | |> foo2 /* comment1 */
+  4 | |> foo3 /* comment2 */
+  5 | |> kochabCooieGameOnOboleUnweave"
+`;
+
 exports[`fsharp_style_pipeline_operator.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -203,6 +213,16 @@ exports[`fsharp_style_pipeline_operator.js format[oxc] 1`] = `
   5 |   |> x => x + '!'"
 `;
 
+exports[`fsharp_style_pipeline_operator.js format[yuku] 1`] = `
+"Unexpected token '>' (2:4)
+  1 | promise
+> 2 |   |> await
+    |    ^
+  3 |   |> x => doubleSay(x, ', ')
+  4 |   |> capitalize
+  5 |   |> x => x + '!'"
+`;
+
 exports[`hack_pipeline_operator.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -355,6 +375,15 @@ exports[`hack_pipeline_operator.js format[oxc] 1`] = `
   4 |   |> await %"
 `;
 
+exports[`hack_pipeline_operator.js format[yuku] 1`] = `
+"Unexpected token '>' (1:4)
+> 1 | a |> await % |> % * 3;
+    |    ^
+  2 |
+  3 | foo
+  4 |   |> await %"
+`;
+
 exports[`minimal_pipeline_operator.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -503,3 +532,12 @@ exports[`minimal_pipeline_operator.js format[oxc] 1`] = `
   3 | a |> (b |> c);
   4 |"
 `;
+
+exports[`minimal_pipeline_operator.js format[yuku] 1`] = `
+"Unexpected token '>' (1:4)
+> 1 | a |> b |> c;
+    |    ^
+  2 |
+  3 | a |> (b |> c);
+  4 |"
+`;

tests/format/js/pipeline-operator/format.test.js

@@ -5,5 +5,6 @@ runFormatTest(import.meta, ["babel"], {
     meriyah: true,
     oxc: true,
     "oxc-ts": true,
+    yuku: true,
   },
 });

tests/format/js/reserved-word/__snapshots__/format.test.js.snap

@@ -50,6 +50,16 @@ var let = "foo";
 ================================================================================
 `;
 
+exports[`let.js format[yuku] 1`] = `
+"Unexpected token '.' in binding pattern (2:4)
+  1 | foo.let;
+> 2 | let.foo;
+    |    ^
+  3 | new let();
+  4 | ({ let: "foo" });
+  5 | (let, "foo");"
+`;
+
 exports[`yield.js format 1`] = `
 ====================================options=====================================
 parsers: ["acorn", "espree", "meriyah", "babel"]

tests/format/js/reserved-word/format.test.js

@@ -1 +1,3 @@
-runFormatTest(import.meta, ["acorn", "espree", "meriyah", "babel"]);
+runFormatTest(import.meta, ["acorn", "espree", "meriyah", "babel"], {
+  errors: { yuku: ["let.js"] },
+});

tests/format/js/source-phase-imports/__snapshots__/format.test.js.snap

@@ -124,6 +124,13 @@ exports[`import-source-attributes-expression.js format[meriyah] 1`] = `
 Cause: [1:7-1:13]: The only valid meta property for import is 'import.meta'"
 `;
 
+exports[`import-source-attributes-expression.js format[yuku] 1`] = `
+"Expected ')' after import(), but found ',' (1:18)
+> 1 | import.source("x", { with: { attr: "val" } });
+    |                  ^
+  2 |"
+`;
+
 exports[`import-source-binding-from.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -161,6 +168,13 @@ exports[`import-source-binding-from.js format[meriyah] 1`] = `
 Cause: [1:19-1:23]: Import source must be string"
 `;
 
+exports[`import-source-binding-from.js format[yuku] 1`] = `
+"Expected module specifier, but found 'from' (1:20)
+> 1 | import source from from "x";
+    |                    ^^^^
+  2 |"
+`;
+
 exports[`import-source-binding-source.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -282,6 +296,13 @@ exports[`no-named.js format[oxc] 1`] = `
   2 |"
 `;
 
+exports[`no-named.js format[yuku] 1`] = `
+"Expected 'from' after import clause, but found '{' (1:15)
+> 1 | import source { x } from "x";
+    |               ^
+  2 |"
+`;
+
 exports[`no-namespace.js format[__babel_estree] 1`] = `
 "Only \`import source x from "./module"\` is valid. (1:15)
 > 1 | import source * as x from "x";
@@ -328,3 +349,10 @@ exports[`no-namespace.js format[oxc] 1`] = `
     |        ^^^^^^
   2 |"
 `;
+
+exports[`no-namespace.js format[yuku] 1`] = `
+"Expected 'from' after import clause, but found '*' (1:15)
+> 1 | import source * as x from "x";
+    |               ^
+  2 |"
+`;

tests/format/js/source-phase-imports/format.test.js

@@ -15,6 +15,11 @@ runFormatTest(import.meta, ["babel"], {
     meriyah: [...importSourceTests, ...invalidSyntaxTests],
     oxc: invalidSyntaxTests,
     "oxc-ts": invalidSyntaxTests,
+    yuku: [
+      "import-source-attributes-expression.js",
+      "import-source-binding-from.js",
+      ...invalidSyntaxTests,
+    ],
     babel: invalidSyntaxTests,
     __babel_estree: invalidSyntaxTests,
   },

tests/format/js/throw_expressions/__snapshots__/format.test.js.snap

@@ -91,3 +91,12 @@ exports[`throw_expression.js format[oxc] 1`] = `
   3 | lint(ast, {
   4 |   with: () => throw new Error("avoid using 'with' statements.")"
 `;
+
+exports[`throw_expression.js format[yuku] 1`] = `
+"'throw' is reserved and cannot be used as an identifier (1:26)
+> 1 | function save(filename = throw new TypeError("Argument required")) {}
+    |                          ^^^^^
+  2 |
+  3 | lint(ast, {
+  4 |   with: () => throw new Error("avoid using 'with' statements.")"
+`;

tests/format/js/throw_expressions/format.test.js

@@ -5,5 +5,6 @@ runFormatTest(import.meta, ["babel"], {
     meriyah: true,
     oxc: true,
     "oxc-ts": true,
+    yuku: true,
   },
 });

tests/format/js/v8_intrinsic/__snapshots__/format.test.js.snap

@@ -50,6 +50,14 @@ exports[`avoid-conflicts-to-pipeline.js format[oxc] 1`] = `
   3 |"
 `;
 
+exports[`avoid-conflicts-to-pipeline.js format[yuku] 1`] = `
+"Unexpected token '%' (2:16)
+  1 | // |>
+> 2 | const status = %GetOptimizationStatus(fn);
+    |                ^
+  3 |"
+`;
+
 exports[`intrinsic_call.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel"]
@@ -137,3 +145,13 @@ exports[`intrinsic_call.js format[oxc] 1`] = `
   4 |                 foo )
   5 |   }"
 `;
+
+exports[`intrinsic_call.js format[yuku] 1`] = `
+"Unexpected token '%' (2:13)
+  1 | function doSmth()     {
+> 2 |             %DebugPrint
+    |             ^
+  3 |         (
+  4 |                 foo )
+  5 |   }"
+`;

tests/format/js/v8_intrinsic/format.test.js

@@ -5,5 +5,6 @@ runFormatTest(import.meta, ["babel"], {
     meriyah: true,
     oxc: true,
     "oxc-ts": true,
+    yuku: true,
   },
 });

tests/format/jsx/do/__snapshots__/format.test.js.snap

@@ -63,3 +63,13 @@ exports[`do.js format[oxc] 1`] = `
   4 |   }}
   5 | </div>"
 `;
+
+exports[`do.js format[yuku] 1`] = `
+"'do' is reserved and cannot be used as an identifier (2:4)
+  1 | <div>
+> 2 |   {do {
+    |    ^^
+  3 | 	  1
+  4 |   }}
+  5 | </div>"
+`;

tests/format/jsx/do/format.test.js

@@ -5,5 +5,6 @@ runFormatTest(import.meta, ["babel"], {
     meriyah: ["do.js"],
     oxc: ["do.js"],
     "oxc-ts": ["do.js"],
+    yuku: ["do.js"],
   },
 });

tests/unit/builtin-plugins.js

@@ -48,6 +48,7 @@ test("builtin parsers", async () => {
       "typescript",
       "vue",
       "yaml",
+      "yuku",
     ]
   `);
 });

website/playground/codeSamples.mjs

@@ -5,6 +5,7 @@ export default function getCodeSamples(parser) {
     case "espree":
     case "meriyah":
     case "oxc":
+    case "yuku":
       return [
         'function HelloWorld({greeting = "hello", greeted = \'"World"\', silent = false, onMouseOver,}) {',
         "",

website/playground/panel/language.js

@@ -15,6 +15,7 @@ function getCodemirrorMode(parser) {
     case "espree":
     case "meriyah":
     case "oxc":
+    case "yuku":
       return "JSX";
 
     case "doc-explorer":

yarn.lock

@@ -3061,6 +3061,99 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@yuku-parser/binding-darwin-arm64@npm:0.6.2":
+  version: 0.6.2
+  resolution: "@yuku-parser/binding-darwin-arm64@npm:0.6.2"
+  conditions: os=darwin & cpu=arm64
+  languageName: node
+  linkType: hard
+
+"@yuku-parser/binding-darwin-x64@npm:0.6.2":
+  version: 0.6.2
+  resolution: "@yuku-parser/binding-darwin-x64@npm:0.6.2"
+  conditions: os=darwin & cpu=x64
+  languageName: node
+  linkType: hard
+
+"@yuku-parser/binding-freebsd-x64@npm:0.6.2":
+  version: 0.6.2
+  resolution: "@yuku-parser/binding-freebsd-x64@npm:0.6.2"
+  conditions: os=freebsd & cpu=x64
+  languageName: node
+  linkType: hard
+
+"@yuku-parser/binding-linux-arm-gnu@npm:0.6.2":
+  version: 0.6.2
+  resolution: "@yuku-parser/binding-linux-arm-gnu@npm:0.6.2"
+  conditions: os=linux & cpu=arm & libc=glibc
+  languageName: node
+  linkType: hard
+
+"@yuku-parser/binding-linux-arm-musl@npm:0.6.2":
+  version: 0.6.2
+  resolution: "@yuku-parser/binding-linux-arm-musl@npm:0.6.2"
+  conditions: os=linux & cpu=arm & libc=musl
+  languageName: node
+  linkType: hard
+
+"@yuku-parser/binding-linux-arm64-gnu@npm:0.6.2":
+  version: 0.6.2
+  resolution: "@yuku-parser/binding-linux-arm64-gnu@npm:0.6.2"
+  conditions: os=linux & cpu=arm64 & libc=glibc
+  languageName: node
+  linkType: hard
+
+"@yuku-parser/binding-linux-arm64-musl@npm:0.6.2":
+  version: 0.6.2
+  resolution: "@yuku-parser/binding-linux-arm64-musl@npm:0.6.2"
+  conditions: os=linux & cpu=arm64 & libc=musl
+  languageName: node
+  linkType: hard
+
+"@yuku-parser/binding-linux-x64-gnu@npm:0.6.2":
+  version: 0.6.2
+  resolution: "@yuku-parser/binding-linux-x64-gnu@npm:0.6.2"
+  conditions: os=linux & cpu=x64 & libc=glibc
+  languageName: node
+  linkType: hard
+
+"@yuku-parser/binding-linux-x64-musl@npm:0.6.2":
+  version: 0.6.2
+  resolution: "@yuku-parser/binding-linux-x64-musl@npm:0.6.2"
+  conditions: os=linux & cpu=x64 & libc=musl
+  languageName: node
+  linkType: hard
+
+"@yuku-parser/binding-win32-arm64@npm:0.6.2":
+  version: 0.6.2
+  resolution: "@yuku-parser/binding-win32-arm64@npm:0.6.2"
+  conditions: os=win32 & cpu=arm64
+  languageName: node
+  linkType: hard
+
+"@yuku-parser/binding-win32-x64@npm:0.6.2":
+  version: 0.6.2
+  resolution: "@yuku-parser/binding-win32-x64@npm:0.6.2"
+  conditions: os=win32 & cpu=x64
+  languageName: node
+  linkType: hard
+
+"@yuku-parser/wasm@npm:0.6.2":
+  version: 0.6.2
+  resolution: "@yuku-parser/wasm@npm:0.6.2"
+  dependencies:
+    "@yuku-toolchain/types": "npm:0.5.43"
+  checksum: 10/95b8aed6a90feb7da5fe7697d68877630306fc5656270d4f47ed739e1cb7ed85a165d0aaa7efd89e6c77fb1339689744281149afa97e663b4ff3a05acd33f2fa
+  languageName: node
+  linkType: hard
+
+"@yuku-toolchain/types@npm:0.5.43":
+  version: 0.5.43
+  resolution: "@yuku-toolchain/types@npm:0.5.43"
+  checksum: 10/ee3d3ac6622aba378c69c7a3e1164adbdd11b977dcb32d410e0e565733bdc1ff4c066d44f7b9d9442713ecc778bc53a191ddea518eb63d1635c034334f43517d
+  languageName: node
+  linkType: hard
+
 "abbrev@npm:^5.0.0":
   version: 5.0.0
   resolution: "abbrev@npm:5.0.0"
@@ -8228,6 +8321,7 @@ __metadata:
     "@typescript-eslint/parser": "npm:8.64.0"
     "@typescript-eslint/typescript-estree": "npm:8.64.0"
     "@typescript-eslint/visitor-keys": "npm:8.64.0"
+    "@yuku-parser/wasm": "npm:0.6.2"
     acorn: "npm:8.17.0"
     acorn-jsx: "npm:5.3.2"
     angular-estree-parser: "npm:15.5.0"
@@ -8358,6 +8452,7 @@ __metadata:
     yaml: "npm:2.9.0"
     yaml-test-suite: "npm:0.1.0"
     yaml-unist-parser: "npm:3.2.0"
+    yuku-parser: "npm:0.6.2"
   bin:
     prettier: ./bin/prettier.cjs
   languageName: unknown
@@ -10112,6 +10207,49 @@ __metadata:
   languageName: node
   linkType: hard
 
+"yuku-parser@npm:0.6.2":
+  version: 0.6.2
+  resolution: "yuku-parser@npm:0.6.2"
+  dependencies:
+    "@yuku-parser/binding-darwin-arm64": "npm:0.6.2"
+    "@yuku-parser/binding-darwin-x64": "npm:0.6.2"
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+    "@yuku-parser/binding-linux-x64-musl":
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+    "@yuku-parser/binding-win32-arm64":
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+    "@yuku-parser/binding-win32-x64":
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   resolution: "zeptomatch-escape@npm:1.0.1"