Infer source type from filepath (#13772)

src/language-js/parse/acorn.js

@@ -3,15 +3,16 @@ import createError from "../../common/parser-create-error.js";
 import tryCombinations from "../../utils/try-combinations.js";
 import createParser from "./utils/create-parser.js";
 import postprocess from "./postprocess/index.js";
+import getSourceType from "./utils/get-source-type.js";
 
 const require = createRequire(import.meta.url);
 
 /** @type {import("acorn").Options} */
 const parseOptions = {
   ecmaVersion: "latest",
-  sourceType: "module",
+  // sourceType: "module",
   allowReturnOutsideFunction: true,
-  allowImportExportEverywhere: true,
+  // allowImportExportEverywhere: true,
   allowSuperOutsideMethod: true,
   locations: true,
   ranges: true,
@@ -55,6 +56,7 @@ function parseWithOptions(text, sourceType) {
   const ast = parser.parse(text, {
     ...parseOptions,
     sourceType,
+    allowImportExportEverywhere: sourceType === "module",
     onComment: comments,
     onToken: tokens,
   });
@@ -65,14 +67,15 @@ function parseWithOptions(text, sourceType) {
 }
 
 function parse(text, options = {}) {
-  const { result: ast, error: moduleParseError } = tryCombinations(
-    () => parseWithOptions(text, /* sourceType */ "module"),
-    () => parseWithOptions(text, /* sourceType */ "script")
+  const sourceType = getSourceType(options);
+  const combinations = (sourceType ? [sourceType] : ["module", "script"]).map(
+    (sourceType) => () => parseWithOptions(text, sourceType)
   );
 
+  const { result: ast, error } = tryCombinations(combinations);
+
   if (!ast) {
-    // throw the error for `module` parsing
-    throw createParseError(moduleParseError);
+    throw createParseError(error);
   }
 
   options.originalText = text;

src/language-js/parse/babel.js

@@ -6,6 +6,7 @@ import jsonParsers from "../../language-json/parser-json.js";
 import createParser from "./utils/create-parser.js";
 import createBabelParseError from "./utils/create-babel-parse-error.js";
 import postprocess from "./postprocess/index.js";
+import getSourceType from "./utils/get-source-type.js";
 
 /**
  * @typedef {import("@babel/parser").parse | import("@babel/parser").parseExpression} Parse
@@ -106,7 +107,8 @@ function createParse(parseMethod, ...optionsCombinations) {
     }
 
     let combinations = optionsCombinations;
-    if (opts.__babelSourceType === "script") {
+    const sourceType = opts.__babelSourceType ?? getSourceType(opts);
+    if (sourceType === "script") {
       combinations = combinations.map((options) => ({
         ...options,
         sourceType: "script",
@@ -143,7 +145,7 @@ function createParse(parseMethod, ...optionsCombinations) {
     const parseFunction =
       parseMethod === "parseExpression" ? parseExpression : babelParse;
     const { result: ast, error } = tryCombinations(
-      ...combinations.map(
+      combinations.map(
         (options) => () => parseWithOptions(parseFunction, text, options)
       )
     );

src/language-js/parse/espree.js

@@ -3,6 +3,7 @@ import createError from "../../common/parser-create-error.js";
 import tryCombinations from "../../utils/try-combinations.js";
 import createParser from "./utils/create-parser.js";
 import postprocess from "./postprocess/index.js";
+import getSourceType from "./utils/get-source-type.js";
 
 const require = createRequire(import.meta.url);
 
@@ -38,14 +39,16 @@ function createParseError(error) {
 function parse(text, options = {}) {
   const { parse: espreeParse } = require("espree");
 
-  const { result: ast, error: moduleParseError } = tryCombinations(
-    () => espreeParse(text, { ...parseOptions, sourceType: "module" }),
-    () => espreeParse(text, { ...parseOptions, sourceType: "script" })
+  const sourceType = getSourceType(options);
+  const combinations = (sourceType ? [sourceType] : ["module", "script"]).map(
+    (/** @type {"module"|"script"} */ sourceType) => () =>
+      espreeParse(text, { ...parseOptions, sourceType })
   );
 
+  const { result: ast, error } = tryCombinations(combinations);
+
   if (!ast) {
-    // throw the error for `module` parsing
-    throw createParseError(moduleParseError);
+    throw createParseError(error);
   }
 
   options.originalText = text;

src/language-js/parse/meriyah.js

@@ -2,11 +2,12 @@ import createError from "../../common/parser-create-error.js";
 import tryCombinations from "../../utils/try-combinations.js";
 import createParser from "./utils/create-parser.js";
 import postprocess from "./postprocess/index.js";
+import getSourceType from "./utils/get-source-type.js";
 
 // https://github.com/meriyah/meriyah/blob/4676f60b6c149d7082bde2c9147f9ae2359c8075/src/parser.ts#L185
 const parseOptions = {
   // Allow module code
-  module: true,
+  // module: true,
   // Enable stage 3 support (ESNext)
   next: true,
   // Enable start and end offsets to each node
@@ -39,14 +40,14 @@ const parseOptions = {
   uniqueKeyInPattern: false,
 };
 
-function parseWithOptions(parse, text, module) {
+function parseWithOptions(parse, text, sourceType) {
   const comments = [];
   const tokens = [];
 
   /** @type {any} */
   const ast = parse(text, {
     ...parseOptions,
-    module,
+    module: sourceType === "module",
     onComment: comments,
     onToken: tokens,
   });
@@ -86,14 +87,15 @@ function createParseError(error) {
 
 async function parse(text, options = {}) {
   const { parse } = await import("meriyah");
-  const { result: ast, error: moduleParseError } = tryCombinations(
-    () => parseWithOptions(parse, text, /* module */ true),
-    () => parseWithOptions(parse, text, /* module */ false)
+
+  const sourceType = getSourceType(options);
+  const combinations = (sourceType ? [sourceType] : ["module", "script"]).map(
+    (sourceType) => () => parseWithOptions(parse, text, sourceType)
   );
+  const { result: ast, error } = tryCombinations(combinations);
 
   if (!ast) {
-    // Throw the error for `module` parsing
-    throw createParseError(moduleParseError);
+    throw createParseError(error);
   }
 
   options.originalText = text;

src/language-js/parse/typescript.js

@@ -42,16 +42,16 @@ async function parse(text, options = {}) {
   const { parseWithNodeMaps } = await import(
     "@typescript-eslint/typescript-estree/dist/parser.js"
   );
-  const { result, error: firstError } = tryCombinations(
+  const { result, error } = tryCombinations([
     // Try passing with our best guess first.
     () => parseWithNodeMaps(textToParse, { ...parseOptions, jsx }),
     // But if we get it wrong, try the opposite.
-    () => parseWithNodeMaps(textToParse, { ...parseOptions, jsx: !jsx })
-  );
+    () => parseWithNodeMaps(textToParse, { ...parseOptions, jsx: !jsx }),
+  ]);
 
   if (!result) {
     // Suppose our guess is correct, throw the first error
-    throw createParseError(firstError);
+    throw createParseError(error);
   }
 
   options.originalText = text;

src/language-js/parse/utils/get-source-type.js

@@ -0,0 +1,18 @@
+/** @returns {"module" | "script" | undefined} */
+function getSourceType(options) {
+  let { filepath } = options;
+  if (!filepath) {
+    return;
+  }
+  filepath = filepath.toLowerCase();
+
+  if (filepath.endsWith(".cjs")) {
+    return "script";
+  }
+
+  if (filepath.endsWith(".mjs")) {
+    return "module";
+  }
+}
+
+export default getSourceType;

src/utils/try-combinations.js

@@ -1,4 +1,4 @@
-function tryCombinations(...combinations) {
+function tryCombinations(combinations) {
   let firstError;
   for (const [index, fn] of combinations.entries()) {
     try {

tests/format/misc/errors/js/known-source-type/__snapshots__/jsfmt.spec.js.snap

@@ -0,0 +1,55 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`snippet: #0 [acorn] format 1`] = `
+"'import' and 'export' may appear only with 'sourceType: module' (1:1)
+> 1 | import "foo"
+    | ^"
+`;
+
+exports[`snippet: #0 [espree] format 1`] = `
+"'import' and 'export' may appear only with 'sourceType: module' (1:1)
+> 1 | import "foo"
+    | ^"
+`;
+
+exports[`snippet: #0 [meriyah] format 1`] = `
+"The import keyword can only be used with the module goal (1:12)
+> 1 | import "foo"
+    |            ^"
+`;
+
+exports[`snippet: #1 [acorn] format 1`] = `
+"'with' in strict mode (1:1)
+> 1 | with(foo) {}
+    | ^"
+`;
+
+exports[`snippet: #1 [espree] format 1`] = `
+"'with' in strict mode (1:1)
+> 1 | with(foo) {}
+    | ^"
+`;
+
+exports[`snippet: #1 [meriyah] format 1`] = `
+"Strict mode code may not include a with statement (1:5)
+> 1 | with(foo) {}
+    |     ^"
+`;
+
+exports[`snippet: #2 [acorn] format 1`] = `
+"Deleting local variable in strict mode (1:1)
+> 1 | delete foo
+    | ^"
+`;
+
+exports[`snippet: #2 [espree] format 1`] = `
+"Deleting local variable in strict mode (1:1)
+> 1 | delete foo
+    | ^"
+`;
+
+exports[`snippet: #2 [meriyah] format 1`] = `
+"Calling delete on expression not allowed in strict mode (1:10)
+> 1 | delete foo
+    |          ^"
+`;

tests/format/misc/errors/js/known-source-type/jsfmt.spec.js

@@ -0,0 +1,20 @@
+run_spec(
+  {
+    importMeta: import.meta,
+    snippets: [
+      {
+        code: 'import "foo"',
+        filename: "script.cjs",
+      },
+      {
+        code: "with(foo) {}",
+        filename: "module.mjs",
+      },
+      {
+        code: "delete foo",
+        filename: "module.mJs",
+      },
+    ],
+  },
+  ["acorn", "espree", "meriyah"]
+);