Migrate JS language to ES Module (#12342)

.eslintrc.cjs

@@ -177,7 +177,6 @@ module.exports = {
         "src/config/**/*.js",
         "src/document/**/*.js",
         "src/language-html/**/*.js",
-        "src/language-js/**/*.js",
         "src/main/**/*.js",
         "src/utils/**/*.js",
         "scripts/tools/eslint-plugin-prettier-internal-rules/**/*.js",

scripts/build/bundler.mjs

@@ -86,10 +86,7 @@ function* getEsbuildOptions(bundle, buildOptions) {
     };
 
     // Replace parser getters with `undefined`
-    for (const file of [
-      "src/language-html/parsers.js",
-      "src/language-js/parse/parsers.js",
-    ]) {
+    for (const file of ["src/language-html/parsers.js"]) {
       replaceModule[path.join(PROJECT_ROOT, file)] = EMPTY_MODULE_REPLACEMENT;
     }
     for (const file of [
@@ -97,7 +94,7 @@ function* getEsbuildOptions(bundle, buildOptions) {
       "src/language-graphql/parsers.js",
       "src/language-handlebars/parsers.js",
       // "src/language-html/parsers.js",
-      // "src/language-js/parse/parsers.js",
+      "src/language-js/parse/parsers.js",
       "src/language-markdown/parsers.js",
       "src/language-yaml/parsers.js",
     ]) {

scripts/build/config.mjs

@@ -26,6 +26,7 @@ const { require } = createEsmUtils(import.meta);
 const parsers = [
   {
     input: "src/language-js/parse/babel.js",
+    isEsm: true,
   },
   {
     input: "src/language-js/parse/flow.js",
@@ -33,6 +34,7 @@ const parsers = [
       // `flow-parser` use this for `globalThis`, can't work in strictMode
       "(function(){return this}())": '(new Function("return this")())',
     },
+    isEsm: true,
   },
   {
     input: "src/language-js/parse/typescript.js",
@@ -94,6 +96,7 @@ const parsers = [
     replaceModule: {
       [require.resolve("debug")]: require.resolve("./shims/debug.cjs"),
     },
+    isEsm: true,
   },
   {
     input: "src/language-js/parse/acorn-and-espree.js",
@@ -104,15 +107,18 @@ const parsers = [
       "const Syntax = ": "const Syntax = undefined && ",
       "var visitorKeys = ": "var visitorKeys = undefined && ",
     },
+    isEsm: true,
   },
   {
     input: "src/language-js/parse/meriyah.js",
+    isEsm: true,
   },
   {
     input: "src/language-js/parse/angular.js",
     replace: {
       "@angular/compiler/src": "@angular/compiler/esm2015/src",
     },
+    isEsm: true,
   },
   {
     input: "src/language-css/parser-postcss.js",

scripts/build/esbuild-plugins/replace-module.mjs

@@ -26,7 +26,8 @@ export default function esbuildPluginReplaceModule(replacements = {}) {
         // Make this work with `@esbuild-plugins/node-modules-polyfill` plugin
         if (
           !resolveDir &&
-          namespace === "node-modules-polyfills-commonjs" &&
+          (namespace === "node-modules-polyfills-commonjs" ||
+            namespace === "node-modules-polyfills") &&
           file
         ) {
           resolveDir = dirname(file);

src/language-css/pragma.js

@@ -1,15 +1,17 @@
-import jsPragma from "../language-js/pragma.js";
+import {
+  hasPragma as jsHasPragma,
+  insertPragma as jsInsertPragma,
+} from "../language-js/pragma.js";
 import parseFrontMatter from "../utils/front-matter/parse.js";
 
 function hasPragma(text) {
-  return jsPragma.hasPragma(parseFrontMatter(text).content);
+  return jsHasPragma(parseFrontMatter(text).content);
 }
 
 function insertPragma(text) {
   const { frontMatter, content } = parseFrontMatter(text);
   return (
-    (frontMatter ? frontMatter.raw + "\n\n" : "") +
-    jsPragma.insertPragma(content)
+    (frontMatter ? frontMatter.raw + "\n\n" : "") + jsInsertPragma(content)
   );
 }
 

src/language-js/clean.js

@@ -1,6 +1,4 @@
-"use strict";
-
-const isBlockComment = require("./utils/is-block-comment.js");
+import isBlockComment from "./utils/is-block-comment.js";
 
 const ignoredProperties = new Set([
   "range",
@@ -212,4 +210,4 @@ function clean(ast, newObj, parent) {
 
 clean.ignoredProperties = ignoredProperties;
 
-module.exports = clean;
+export default clean;

src/language-js/comments.js

@@ -1,6 +1,4 @@
-"use strict";
-
-const {
+import {
   getLast,
   hasNewline,
   getNextNonSpaceNonCommentCharacterIndexWithStartIndex,
@@ -11,8 +9,8 @@ const {
   addDanglingComment,
   getNextNonSpaceNonCommentCharacterIndex,
   isNonEmptyArray,
-} = require("../common/util.js");
-const {
+} from "../common/util.js";
+import {
   getFunctionParameters,
   isPrettierIgnoreComment,
   isJsxNode,
@@ -28,9 +26,9 @@ const {
   getComments,
   CommentCheckFlags,
   markerForIfWithoutBlockAndSameLineComment,
-} = require("./utils/index.js");
-const { locStart, locEnd } = require("./loc.js");
-const isBlockComment = require("./utils/is-block-comment.js");
+} from "./utils/index.js";
+import { locStart, locEnd } from "./loc.js";
+import isBlockComment from "./utils/is-block-comment.js";
 
 /**
  * @typedef {import("./types/estree").Node} Node
@@ -1026,7 +1024,7 @@ function willPrintOwnComments(path /*, options */) {
   );
 }
 
-module.exports = {
+export {
   handleOwnLineComment,
   handleEndOfLineComment,
   handleRemainingComment,

src/language-js/embed.js

@@ -1,14 +1,12 @@
-"use strict";
-
-const {
+import {
   hasComment,
   CommentCheckFlags,
   isObjectProperty,
-} = require("./utils/index.js");
-const formatMarkdown = require("./embed/markdown.js");
-const formatCss = require("./embed/css.js");
-const formatGraphql = require("./embed/graphql.js");
-const formatHtml = require("./embed/html.js");
+} from "./utils/index.js";
+import formatMarkdown from "./embed/markdown.js";
+import formatCss from "./embed/css.js";
+import formatGraphql from "./embed/graphql.js";
+import formatHtml from "./embed/html.js";
 
 function getLanguage(path) {
   if (
@@ -302,4 +300,4 @@ function hasInvalidCookedValue({ quasis }) {
   return quasis.some(({ value: { cooked } }) => cooked === null);
 }
 
-module.exports = embed;
+export default embed;

src/language-js/embed/css.js

@@ -1,11 +1,11 @@
-"use strict";
+import { isNonEmptyArray } from "../../common/util.js";
+import doc from "../../document/index.js";
+import { printTemplateExpressions } from "../print/template-literal.js";
 
-const { isNonEmptyArray } = require("../../common/util.js");
 const {
   builders: { indent, hardline, softline },
   utils: { mapDoc, replaceEndOfLine, cleanDoc },
-} = require("../../document/index.js");
-const { printTemplateExpressions } = require("../print/template-literal.js");
+} = doc;
 
 function format(path, print, textToDoc) {
   const node = path.getValue();
@@ -77,4 +77,4 @@ function replacePlaceholders(quasisDoc, expressionDocs) {
   return expressionDocs.length === replaceCounter ? newDoc : null;
 }
 
-module.exports = format;
+export default format;

src/language-js/embed/graphql.js

@@ -1,12 +1,12 @@
-"use strict";
+import doc from "../../document/index.js";
+import {
+  escapeTemplateCharacters,
+  printTemplateExpressions,
+} from "../print/template-literal.js";
 
 const {
   builders: { indent, join, hardline },
-} = require("../../document/index.js");
-const {
-  escapeTemplateCharacters,
-  printTemplateExpressions,
-} = require("../print/template-literal.js");
+} = doc;
 
 function format(path, print, textToDoc) {
   const node = path.getValue();
@@ -105,4 +105,4 @@ function printGraphqlComments(lines) {
   return parts.length === 0 ? null : join(hardline, parts);
 }
 
-module.exports = format;
+export default format;

src/language-js/embed/html.js

@@ -1,13 +1,13 @@
-"use strict";
+import doc from "../../document/index.js";
+import {
+  printTemplateExpressions,
+  uncookTemplateElementValue,
+} from "../print/template-literal.js";
 
 const {
   builders: { indent, line, hardline, group },
   utils: { mapDoc },
-} = require("../../document/index.js");
-const {
-  printTemplateExpressions,
-  uncookTemplateElementValue,
-} = require("../print/template-literal.js");
+} = doc;
 
 // The counter is needed to distinguish nested embeds.
 let htmlTemplateLiteralCounter = 0;
@@ -97,4 +97,4 @@ function format(path, print, textToDoc, options, { parser }) {
   ]);
 }
 
-module.exports = format;
+export default format;

src/language-js/embed/markdown.js

@@ -1,9 +1,9 @@
-"use strict";
+import doc from "../../document/index.js";
+import { escapeTemplateCharacters } from "../print/template-literal.js";
 
 const {
   builders: { indent, softline, literalline, dedentToRoot },
-} = require("../../document/index.js");
-const { escapeTemplateCharacters } = require("../print/template-literal.js");
+} = doc;
 
 function format(path, print, textToDoc) {
   const node = path.getValue();
@@ -37,4 +37,4 @@ function getIndentation(str) {
   return firstMatchedIndent === null ? "" : firstMatchedIndent[1];
 }
 
-module.exports = format;
+export default format;

src/language-js/index.js

@@ -1,10 +1,11 @@
-"use strict";
+import { createRequire } from "module";
+import createLanguage from "../utils/create-language.js";
+import estreePrinter from "./printer-estree.js";
+import estreeJsonPrinter from "./printer-estree-json.js";
+import options from "./options.js";
+import parsers from "./parse/parsers.js";
 
-const createLanguage = require("../utils/create-language.js");
-const estreePrinter = require("./printer-estree.js");
-const estreeJsonPrinter = require("./printer-estree-json.js");
-const options = require("./options.js");
-const parsers = require("./parse/parsers.js");
+const require = createRequire(import.meta.url);
 
 const languages = [
   createLanguage(
@@ -117,9 +118,11 @@ const printers = {
   "estree-json": estreeJsonPrinter,
 };
 
-module.exports = {
+const language = {
   languages,
   options,
   printers,
   parsers,
 };
+
+export default language;

src/language-js/loc.cjs

@@ -0,0 +1,33 @@
+// A cjs version of loc.js to use in `../main/parser.js`
+"use strict";
+
+const isNonEmptyArray = require("../utils/is-non-empty-array.js");
+
+/**
+ * @typedef {import("./types/estree").Node} Node
+ */
+
+function locStart(node, opts) {
+  const { ignoreDecorators } = opts || {};
+
+  // Handle nodes with decorators. They should start at the first decorator
+  if (!ignoreDecorators) {
+    const decorators =
+      (node.declaration && node.declaration.decorators) || node.decorators;
+
+    if (isNonEmptyArray(decorators)) {
+      return locStart(decorators[0]);
+    }
+  }
+
+  return node.range ? node.range[0] : node.start;
+}
+
+function locEnd(node) {
+  return node.range ? node.range[1] : node.end;
+}
+
+module.exports = {
+  locStart,
+  locEnd,
+};

src/language-js/loc.js

@@ -1,6 +1,4 @@
-"use strict";
-
-const isNonEmptyArray = require("../utils/is-non-empty-array.js");
+import isNonEmptyArray from "../utils/is-non-empty-array.js";
 
 /**
  * @typedef {import("./types/estree").Node} Node
@@ -55,9 +53,4 @@ function hasSameLoc(nodeA, nodeB) {
   return hasSameLocStart(nodeA, nodeB) && hasSameLocEnd(nodeA, nodeB);
 }
 
-module.exports = {
-  locStart,
-  locEnd,
-  hasSameLocStart,
-  hasSameLoc,
-};
+export { locStart, locEnd, hasSameLocStart, hasSameLoc };

src/language-js/needs-parens.js

@@ -1,8 +1,6 @@
-"use strict";
-
-const getLast = require("../utils/get-last.js");
-const isNonEmptyArray = require("../utils/is-non-empty-array.js");
-const {
+import getLast from "../utils/get-last.js";
+import isNonEmptyArray from "../utils/is-non-empty-array.js";
+import {
   getFunctionParameters,
   getLeftSidePathName,
   hasFlowShorthandAnnotationComment,
@@ -15,7 +13,7 @@ const {
   isCallExpression,
   isMemberExpression,
   isObjectProperty,
-} = require("./utils/index.js");
+} from "./utils/index.js";
 
 function needsParens(path, options) {
   const parent = path.getParentNode();
@@ -947,4 +945,4 @@ function shouldWrapFunctionForExportDefault(path, options) {
   );
 }
 
-module.exports = needsParens;
+export default needsParens;

src/language-js/options.js

@@ -1,11 +1,9 @@
-"use strict";
-
-const commonOptions = require("../common/common-options.js");
+import commonOptions from "../common/common-options.js";
 
 const CATEGORY_JAVASCRIPT = "JavaScript";
 
 // format based on https://github.com/prettier/prettier/blob/main/src/main/core-options.js
-module.exports = {
+const options = {
   arrowParens: {
     since: "1.9.0",
     category: CATEGORY_JAVASCRIPT,
@@ -100,3 +98,5 @@ module.exports = {
   },
   singleAttributePerLine: commonOptions.singleAttributePerLine,
 };
+
+export default options;

src/language-js/package.json

@@ -1,5 +0,0 @@
-{
-  "//TODO": "Remove this file when we close #10157",
-  "type": "commonjs",
-  "description": "A package.json file to use `.js` files in this directory as CommonJS module."
-}

src/language-js/parse/acorn-and-espree.js

@@ -1,11 +1,11 @@
-"use strict";
+import acorn from "./acorn.js";
+import espree from "./espree.js";
 
-const acorn = require("./acorn.js");
-const espree = require("./espree.js");
-
-module.exports = {
+const parserAcornAndEspree = {
   parsers: {
     acorn,
     espree,
   },
 };
+
+export default parserAcornAndEspree;

src/language-js/parse/acorn.js

@@ -1,9 +1,11 @@
-"use strict";
+// TODO[@fisker]: try inline import these modules
+import { Parser as AcornParser } from "acorn";
+import acornJsx from "acorn-jsx";
 
-const createError = require("../../common/parser-create-error.js");
-const tryCombinations = require("../../utils/try-combinations.js");
-const createParser = require("./utils/create-parser.js");
-const postprocess = require("./postprocess/index.js");
+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";
 
 /** @type {import("acorn").Options} */
 const parseOptions = {
@@ -37,8 +39,6 @@ function createParseError(error) {
 let parser;
 const getParser = () => {
   if (!parser) {
-    const { Parser: AcornParser } = require("acorn");
-    const acornJsx = require("acorn-jsx");
     parser = AcornParser.extend(acornJsx());
   }
   return parser;
@@ -78,4 +78,4 @@ function parse(text, parsers, options = {}) {
   return postprocess(ast, options);
 }
 
-module.exports = createParser(parse);
+export default createParser(parse);

src/language-js/parse/angular.js

@@ -1,10 +1,10 @@
-"use strict";
+// TODO[@fisker]: try inline import this module
+import ngEstreeParser from "angular-estree-parser";
 
-const { locStart, locEnd } = require("../loc.js");
+import { locStart, locEnd } from "../loc.js";
 
 function createParser(_parse) {
   const parse = (text, parsers, options) => {
-    const ngEstreeParser = require("angular-estree-parser");
     const node = _parse(text, ngEstreeParser);
     return {
       type: "NGRoot",
@@ -17,7 +17,7 @@ function createParser(_parse) {
   return { astFormat: "estree", parse, locStart, locEnd };
 }
 
-module.exports = {
+const parser = {
   parsers: {
     __ng_action: createParser((text, ng) => ng.parseAction(text)),
     __ng_binding: createParser((text, ng) => ng.parseBinding(text)),
@@ -25,3 +25,5 @@ module.exports = {
     __ng_directive: createParser((text, ng) => ng.parseTemplateBindings(text)),
   },
 };
+
+export default parser;

src/language-js/parse/babel.js

@@ -1,12 +1,13 @@
-"use strict";
+// TODO[@fisker]: try inline import this module
+import babelParser from "@babel/parser";
 
-const tryCombinations = require("../../utils/try-combinations.js");
-const getShebang = require("../utils/get-shebang.js");
-const getNextNonSpaceNonCommentCharacterIndexWithStartIndex = require("../../utils/text/get-next-non-space-non-comment-character-index-with-start-index.js");
-const createParser = require("./utils/create-parser.js");
-const createBabelParseError = require("./utils/create-babel-parse-error.js");
-const postprocess = require("./postprocess/index.js");
-const jsonParsers = require("./json.js");
+import tryCombinations from "../../utils/try-combinations.js";
+import getShebang from "../utils/get-shebang.js";
+import getNextNonSpaceNonCommentCharacterIndexWithStartIndex from "../../utils/text/get-next-non-space-non-comment-character-index-with-start-index.js";
+import createParser from "./utils/create-parser.js";
+import createBabelParseError from "./utils/create-babel-parse-error.js";
+import postprocess from "./postprocess/index.js";
+import jsonParsers from "./json.js";
 
 /**
  * @typedef {import("@babel/parser").parse | import("@babel/parser").parseExpression} Parse
@@ -86,7 +87,7 @@ function isFlowFile(text, options) {
 function parseWithOptions(parseMethod, text, options) {
   // Inline the require to avoid loading all the JS if we don't use it
   /** @type {Parse} */
-  const parse = require("@babel/parser")[parseMethod];
+  const parse = babelParser[parseMethod];
   const ast = parse(text, options);
   const error = ast.errors.find(
     (error) => !allowedMessageCodes.has(error.reasonCode)
@@ -229,7 +230,7 @@ const babel = createParser(parse);
 const babelExpression = createParser(parseExpression);
 
 // Export as a plugin so we can reuse the same bundle for UMD loading
-module.exports = {
+const parser = {
   parsers: {
     babel,
     "babel-flow": createParser(parseFlow),
@@ -245,3 +246,5 @@ module.exports = {
     __babel_estree: createParser(parseEstree),
   },
 };
+
+export default parser;

src/language-js/parse/espree.js

@@ -1,10 +1,11 @@
-"use strict";
+// TODO[@fisker]: try inline import this module
+import { parse as espreeParse } from "espree";
 
-const createError = require("../../common/parser-create-error.js");
-const tryCombinations = require("../../utils/try-combinations.js");
-const createParser = require("./utils/create-parser.js");
-const replaceHashbang = require("./utils/replace-hashbang.js");
-const postprocess = require("./postprocess/index.js");
+import createError from "../../common/parser-create-error.js";
+import tryCombinations from "../../utils/try-combinations.js";
+import createParser from "./utils/create-parser.js";
+import replaceHashbang from "./utils/replace-hashbang.js";
+import postprocess from "./postprocess/index.js";
 
 /** @type {import("espree").Options} */
 const parseOptions = {
@@ -33,12 +34,10 @@ function createParseError(error) {
 }
 
 function parse(originalText, parsers, options = {}) {
-  const { parse } = require("espree");
-
   const textToParse = replaceHashbang(originalText);
   const { result: ast, error: moduleParseError } = tryCombinations(
-    () => parse(textToParse, { ...parseOptions, sourceType: "module" }),
-    () => parse(textToParse, { ...parseOptions, sourceType: "script" })
+    () => espreeParse(textToParse, { ...parseOptions, sourceType: "module" }),
+    () => espreeParse(textToParse, { ...parseOptions, sourceType: "script" })
   );
 
   if (!ast) {
@@ -50,4 +49,4 @@ function parse(originalText, parsers, options = {}) {
   return postprocess(ast, options);
 }
 
-module.exports = createParser(parse);
+export default createParser(parse);

src/language-js/parse/flow.js

@@ -1,9 +1,11 @@
-"use strict";
+// TODO[@fisker]: try inline import this module
+// Inline the require to avoid loading all the JS if we don't use it
+import flow from "flow-parser";
 
-const createError = require("../../common/parser-create-error.js");
-const createParser = require("./utils/create-parser.js");
-const replaceHashbang = require("./utils/replace-hashbang.js");
-const postprocess = require("./postprocess/index.js");
+import createError from "../../common/parser-create-error.js";
+import createParser from "./utils/create-parser.js";
+import replaceHashbang from "./utils/replace-hashbang.js";
+import postprocess from "./postprocess/index.js";
 
 // https://github.com/facebook/flow/tree/main/packages/flow-parser#options
 // Keep this sync with `/scripts/sync-flow-test.js`
@@ -39,9 +41,7 @@ function createParseError(error) {
 }
 
 function parse(text, parsers, options = {}) {
-  // Inline the require to avoid loading all the JS if we don't use it
-  const { parse } = require("flow-parser");
-  const ast = parse(replaceHashbang(text), parseOptions);
+  const ast = flow.parse(replaceHashbang(text), parseOptions);
   const [error] = ast.errors;
   if (error) {
     throw createParseError(error);
@@ -52,8 +52,10 @@ function parse(text, parsers, options = {}) {
 }
 
 // Export as a plugin so we can reuse the same bundle for UMD loading
-module.exports = {
+const parser = {
   parsers: {
     flow: createParser(parse),
   },
 };
+
+export default parser;

src/language-js/parse/json.js

@@ -1,15 +1,15 @@
-"use strict";
+// TODO[@fisker]: try inline import this module
+import { parseExpression } from "@babel/parser";
 
-const isNonEmptyArray = require("../../utils/is-non-empty-array.js");
-const createError = require("../../common/parser-create-error.js");
-const createParser = require("./utils/create-parser.js");
-const createBabelParseError = require("./utils/create-babel-parse-error.js");
+import isNonEmptyArray from "../../utils/is-non-empty-array.js";
+import createError from "../../common/parser-create-error.js";
+import createParser from "./utils/create-parser.js";
+import createBabelParseError from "./utils/create-babel-parse-error.js";
 
 function createJsonParse(options = {}) {
   const { allowComments = true } = options;
 
   return function parse(text /*, parsers, options*/) {
-    const { parseExpression } = require("@babel/parser");
     let ast;
     try {
       ast = parseExpression(text, {
@@ -145,4 +145,4 @@ const jsonParsers = {
   }),
 };
 
-module.exports = jsonParsers;
+export default jsonParsers;

src/language-js/parse/meriyah.js

@@ -1,9 +1,10 @@
-"use strict";
+// TODO[@fisker]: try inline import this module
+import { parse as meriyahParse } from "meriyah";
 
-const createError = require("../../common/parser-create-error.js");
-const tryCombinations = require("../../utils/try-combinations.js");
-const createParser = require("./utils/create-parser.js");
-const postprocess = require("./postprocess/index.js");
+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";
 
 // https://github.com/meriyah/meriyah/blob/4676f60b6c149d7082bde2c9147f9ae2359c8075/src/parser.ts#L185
 const parseOptions = {
@@ -42,12 +43,11 @@ const parseOptions = {
 };
 
 function parseWithOptions(text, module) {
-  const { parse } = require("meriyah");
   const comments = [];
   const tokens = [];
 
   /** @type {any} */
-  const ast = parse(text, {
+  const ast = meriyahParse(text, {
     ...parseOptions,
     module,
     onComment: comments,
@@ -86,8 +86,10 @@ function parse(text, parsers, options = {}) {
   return postprocess(ast, options);
 }
 
-module.exports = {
+const parser = {
   parsers: {
     meriyah: createParser(parse),
   },
 };
+
+export default parser;

src/language-js/parse/parsers.js

@@ -1,72 +1,79 @@
-"use strict";
+import babel from "./babel.js";
+import flow from "./flow.js";
+import typescript from "./typescript.js";
+import angular from "./angular.js";
+import acornAndEspree from "./acorn-and-espree.js";
+import meriyah from "./meriyah.js";
 
-module.exports = {
+const parsers = {
   // JS - Babel
   get babel() {
-    return require("./babel.js").parsers.babel;
+    return babel.parsers.babel;
   },
   get "babel-flow"() {
-    return require("./babel.js").parsers["babel-flow"];
+    return babel.parsers["babel-flow"];
   },
   get "babel-ts"() {
-    return require("./babel.js").parsers["babel-ts"];
+    return babel.parsers["babel-ts"];
   },
   get json() {
-    return require("./babel.js").parsers.json;
+    return babel.parsers.json;
   },
   get json5() {
-    return require("./babel.js").parsers.json5;
+    return babel.parsers.json5;
   },
   get "json-stringify"() {
-    return require("./babel.js").parsers["json-stringify"];
+    return babel.parsers["json-stringify"];
   },
   get __js_expression() {
-    return require("./babel.js").parsers.__js_expression;
+    return babel.parsers.__js_expression;
   },
   get __vue_expression() {
-    return require("./babel.js").parsers.__vue_expression;
+    return babel.parsers.__vue_expression;
   },
   get __vue_event_binding() {
-    return require("./babel.js").parsers.__vue_event_binding;
+    return babel.parsers.__vue_event_binding;
   },
   // JS - Flow
   get flow() {
-    return require("./flow.js").parsers.flow;
+    return flow.parsers.flow;
   },
   // JS - TypeScript
   get typescript() {
-    return require("./typescript.js").parsers.typescript;
+    return typescript.parsers.typescript;
   },
   // JS - Angular Action
   get __ng_action() {
-    return require("./angular.js").parsers.__ng_action;
+    return angular.parsers.__ng_action;
   },
   // JS - Angular Binding
   get __ng_binding() {
-    return require("./angular.js").parsers.__ng_binding;
+    return angular.parsers.__ng_binding;
   },
   // JS - Angular Interpolation
   get __ng_interpolation() {
-    return require("./angular.js").parsers.__ng_interpolation;
+    return angular.parsers.__ng_interpolation;
   },
   // JS - Angular Directive
   get __ng_directive() {
-    return require("./angular.js").parsers.__ng_directive;
+    return angular.parsers.__ng_directive;
   },
   // JS - acorn
   get acorn() {
-    return require("./acorn-and-espree.js").parsers.acorn;
+    return acornAndEspree.parsers.acorn;
   },
   // JS - espree
   get espree() {
-    return require("./acorn-and-espree.js").parsers.espree;
+    return acornAndEspree.parsers.espree;
   },
   // JS - meriyah
   get meriyah() {
-    return require("./meriyah.js").parsers.meriyah;
+    return meriyah.parsers.meriyah;
   },
   // JS - Babel Estree
   get __babel_estree() {
-    return require("./babel.js").parsers.__babel_estree;
+    return babel.parsers.__babel_estree;
   },
 };
+
+export default parsers;

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

@@ -1,11 +1,9 @@
-"use strict";
-
-const { locStart, locEnd } = require("../../loc.js");
-const isTsKeywordType = require("../../utils/is-ts-keyword-type.js");
-const isTypeCastComment = require("../../utils/is-type-cast-comment.js");
-const getLast = require("../../../utils/get-last.js");
-const visitNode = require("./visit-node.js");
-const { throwErrorForInvalidNodes } = require("./typescript.js");
+import { locStart, locEnd } from "../../loc.js";
+import isTsKeywordType from "../../utils/is-ts-keyword-type.js";
+import isTypeCastComment from "../../utils/is-type-cast-comment.js";
+import getLast from "../../../utils/get-last.js";
+import visitNode from "./visit-node.js";
+import { throwErrorForInvalidNodes } from "./typescript.js";
 
 function postprocess(ast, options) {
   if (
@@ -209,4 +207,4 @@ function rebalanceLogicalTree(node) {
   });
 }
 
-module.exports = postprocess;
+export default postprocess;

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

@@ -1,7 +1,5 @@
-"use strict";
-
-const createError = require("../../../common/parser-create-error.js");
-const visitNode = require("./visit-node.js");
+import createError from "../../../common/parser-create-error.js";
+import visitNode from "./visit-node.js";
 
 function throwSyntaxError(node, message) {
   const { start, end } = node.loc;
@@ -78,4 +76,4 @@ function throwErrorForInvalidNodes(ast, options) {
   });
 }
 
-module.exports = { throwErrorForInvalidNodes };
+export { throwErrorForInvalidNodes };

src/language-js/parse/postprocess/visit-node.js

@@ -1,5 +1,3 @@
-"use strict";
-
 function visitNode(node, fn) {
   if (Array.isArray(node)) {
     // As of Node.js 16 using raw for loop over Array.entries provides a
@@ -24,4 +22,4 @@ function visitNode(node, fn) {
   return node;
 }
 
-module.exports = visitNode;
+export default visitNode;

src/language-js/parse/typescript.js

@@ -1,10 +1,11 @@
-"use strict";
+// TODO[@fisker]: try inline import this module
+import { parseWithNodeMaps } from "@typescript-eslint/typescript-estree";
 
-const createError = require("../../common/parser-create-error.js");
-const tryCombinations = require("../../utils/try-combinations.js");
-const createParser = require("./utils/create-parser.js");
-const replaceHashbang = require("./utils/replace-hashbang.js");
-const postprocess = require("./postprocess/index.js");
+import createError from "../../common/parser-create-error.js";
+import tryCombinations from "../../utils/try-combinations.js";
+import createParser from "./utils/create-parser.js";
+import replaceHashbang from "./utils/replace-hashbang.js";
+import postprocess from "./postprocess/index.js";
 
 /** @type {import("@typescript-eslint/typescript-estree").TSESTreeOptions} */
 const parseOptions = {
@@ -36,7 +37,6 @@ function parse(text, parsers, options = {}) {
   const textToParse = replaceHashbang(text);
   const jsx = isProbablyJsx(text);
 
-  const { parseWithNodeMaps } = require("@typescript-eslint/typescript-estree");
   const { result, error: firstError } = tryCombinations(
     // Try passing with our best guess first.
     () => parseWithNodeMaps(textToParse, { ...parseOptions, jsx }),
@@ -69,8 +69,10 @@ function isProbablyJsx(text) {
 }
 
 // Export as a plugin so we can reuse the same bundle for UMD loading
-module.exports = {
+const parser = {
   parsers: {
     typescript: createParser(parse),
   },
 };
+
+export default parser;

src/language-js/parse/utils/create-babel-parse-error.js

@@ -1,6 +1,4 @@
-"use strict";
-
-const createError = require("../../../common/parser-create-error.js");
+import createError from "../../../common/parser-create-error.js";
 
 function createBabelParseError(error) {
   // babel error prints (l:c) with cols that are zero indexed
@@ -15,4 +13,4 @@ function createBabelParseError(error) {
   });
 }
 
-module.exports = createBabelParseError;
+export default createBabelParseError;

src/language-js/parse/utils/create-parser.js

@@ -1,7 +1,5 @@
-"use strict";
-
-const { hasPragma } = require("../../pragma.js");
-const { locStart, locEnd } = require("../../loc.js");
+import { hasPragma } from "../../pragma.js";
+import { locStart, locEnd } from "../../loc.js";
 
 function createParser(options) {
   options = typeof options === "function" ? { parse: options } : options;
@@ -15,4 +13,4 @@ function createParser(options) {
   };
 }
 
-module.exports = createParser;
+export default createParser;

src/language-js/parse/utils/replace-hashbang.js

@@ -1,5 +1,3 @@
-"use strict";
-
 // Replace `#!` with `//` so `typescript`, `flow`, and `espree` can parse it as line comment
 // Inspired by ESLint parse function https://github.com/eslint/eslint/blob/9d6063add931f0803cae1676d5df307baf114360/lib/linter/linter.js#L635
 function replaceHashbang(text) {
@@ -10,4 +8,4 @@ function replaceHashbang(text) {
   return text;
 }
 
-module.exports = replaceHashbang;
+export default replaceHashbang;

src/language-js/pragma.js

@@ -1,8 +1,6 @@
-"use strict";
-
-const { parseWithComments, strip, extract, print } = require("jest-docblock");
-const { normalizeEndOfLine } = require("../common/end-of-line.js");
-const getShebang = require("./utils/get-shebang.js");
+import { parseWithComments, strip, extract, print } from "jest-docblock";
+import { normalizeEndOfLine } from "../common/end-of-line.js";
+import getShebang from "./utils/get-shebang.js";
 
 function parseDocBlock(text) {
   const shebang = getShebang(text);
@@ -42,7 +40,4 @@ function insertPragma(originalText) {
   );
 }
 
-module.exports = {
-  hasPragma,
-  insertPragma,
-};
+export { hasPragma, insertPragma };

src/language-js/print-preprocess.js

@@ -1,5 +1,3 @@
-"use strict";
-
 function preprocess(ast, options) {
   switch (options.parser) {
     case "json":
@@ -19,4 +17,4 @@ function preprocess(ast, options) {
   }
 }
 
-module.exports = preprocess;
+export default preprocess;

src/language-js/print/angular.js

@@ -1,10 +1,10 @@
-"use strict";
+import doc from "../../document/index.js";
+import { hasNode, hasComment, getComments } from "../utils/index.js";
+import { printBinaryishExpression } from "./binaryish.js";
 
 const {
   builders: { join, line, group },
-} = require("../../document/index.js");
-const { hasNode, hasComment, getComments } = require("../utils/index.js");
-const { printBinaryishExpression } = require("./binaryish.js");
+} = doc;
 
 /** @typedef {import("../../common/ast-path")} AstPath */
 
@@ -125,4 +125,4 @@ function hasNgSideEffect(path) {
   });
 }
 
-module.exports = { printAngular };
+export { printAngular };

src/language-js/print/array.js

@@ -1,21 +1,21 @@
-"use strict";
-
-const { printDanglingComments } = require("../../main/comments.js");
-const {
-  builders: { line, softline, hardline, group, indent, ifBreak, fill },
-} = require("../../document/index.js");
-const { getLast, hasNewline } = require("../../common/util.js");
-const {
+import { printDanglingComments } from "../../main/comments.js";
+import doc from "../../document/index.js";
+import { getLast, hasNewline } from "../../common/util.js";
+import {
   shouldPrintComma,
   hasComment,
   CommentCheckFlags,
   isNextLineEmpty,
   isNumericLiteral,
   isSignedNumericLiteral,
-} = require("../utils/index.js");
-const { locStart } = require("../loc.js");
+} from "../utils/index.js";
+import { locStart } from "../loc.js";
 
-const { printOptionalToken, printTypeAnnotation } = require("./misc.js");
+import { printOptionalToken, printTypeAnnotation } from "./misc.js";
+
+const {
+  builders: { line, softline, hardline, group, indent, ifBreak, fill },
+} = doc;
 
 /** @typedef {import("../../document").Doc} Doc */
 
@@ -186,4 +186,4 @@ function printArrayItemsConcisely(path, options, print, trailingComma) {
   return fill(parts);
 }
 
-module.exports = { printArray, printArrayItems, isConciselyPrintedArray };
+export { printArray, printArrayItems, isConciselyPrintedArray };

src/language-js/print/assignment.js

@@ -1,11 +1,6 @@
-"use strict";
-
-const { isNonEmptyArray, getStringWidth } = require("../../common/util.js");
-const {
-  builders: { line, group, indent, indentIfBreak },
-  utils: { cleanDoc, willBreak, canBreak },
-} = require("../../document/index.js");
-const {
+import { isNonEmptyArray, getStringWidth } from "../../common/util.js";
+import doc from "../../document/index.js";
+import {
   hasLeadingOwnLineComment,
   isBinaryish,
   isStringLiteral,
@@ -18,9 +13,14 @@ const {
   hasComment,
   isSignedNumericLiteral,
   isObjectProperty,
-} = require("../utils/index.js");
-const { shouldInlineLogicalExpression } = require("./binaryish.js");
-const { printCallExpression } = require("./call-expression.js");
+} from "../utils/index.js";
+import { shouldInlineLogicalExpression } from "./binaryish.js";
+import { printCallExpression } from "./call-expression.js";
+
+const {
+  builders: { line, group, indent, indentIfBreak },
+  utils: { cleanDoc, willBreak, canBreak },
+} = doc;
 
 function printAssignment(
   path,
@@ -462,7 +462,7 @@ function getTypeArgumentsFromCallExpression(node) {
   );
 }
 
-module.exports = {
+export {
   printVariableDeclarator,
   printAssignmentExpression,
   printAssignment,

src/language-js/print/binaryish.js

@@ -1,7 +1,19 @@
-"use strict";
+import { printComments } from "../../main/comments.js";
+import { getLast } from "../../common/util.js";
+import doc from "../../document/index.js";
+import {
+  hasLeadingOwnLineComment,
+  isBinaryish,
+  isJsxNode,
+  shouldFlatten,
+  hasComment,
+  CommentCheckFlags,
+  isCallExpression,
+  isMemberExpression,
+  isObjectProperty,
+  isEnabledHackPipeline,
+} from "../utils/index.js";
 
-const { printComments } = require("../../main/comments.js");
-const { getLast } = require("../../common/util.js");
 const {
   builders: {
     join,
@@ -14,19 +26,7 @@ const {
     indentIfBreak,
   },
   utils: { cleanDoc, getDocParts, isConcat },
-} = require("../../document/index.js");
-const {
-  hasLeadingOwnLineComment,
-  isBinaryish,
-  isJsxNode,
-  shouldFlatten,
-  hasComment,
-  CommentCheckFlags,
-  isCallExpression,
-  isMemberExpression,
-  isObjectProperty,
-  isEnabledHackPipeline,
-} = require("../utils/index.js");
+} = doc;
 
 /** @typedef {import("../../document").Doc} Doc */
 
@@ -337,4 +337,4 @@ function shouldInlineLogicalExpression(node) {
   return false;
 }
 
-module.exports = { printBinaryishExpression, shouldInlineLogicalExpression };
+export { printBinaryishExpression, shouldInlineLogicalExpression };

src/language-js/print/block.js

@@ -1,18 +1,18 @@
-"use strict";
-
-const { printDanglingComments } = require("../../main/comments.js");
-const { isNonEmptyArray } = require("../../common/util.js");
-const {
-  builders: { hardline, indent },
-} = require("../../document/index.js");
-const {
+import { printDanglingComments } from "../../main/comments.js";
+import { isNonEmptyArray } from "../../common/util.js";
+import doc from "../../document/index.js";
+import {
   hasComment,
   CommentCheckFlags,
   isNextLineEmpty,
-} = require("../utils/index.js");
-const { printHardlineAfterHeritage } = require("./class.js");
+} from "../utils/index.js";
+import { printHardlineAfterHeritage } from "./class.js";
 
-const { printBody } = require("./statement.js");
+import { printBody } from "./statement.js";
+
+const {
+  builders: { hardline, indent },
+} = doc;
 
 /** @typedef {import("../../document").Doc} Doc */
 
@@ -107,4 +107,4 @@ function printBlockBody(path, options, print) {
   return parts;
 }
 
-module.exports = { printBlock, printBlockBody };
+export { printBlock, printBlockBody };

src/language-js/print/call-arguments.js

@@ -1,8 +1,6 @@
-"use strict";
-
-const { printDanglingComments } = require("../../main/comments.js");
-const { getLast, getPenultimate } = require("../../common/util.js");
-const {
+import { printDanglingComments } from "../../main/comments.js";
+import { getLast, getPenultimate } from "../../common/util.js";
+import {
   getFunctionParameters,
   hasComment,
   CommentCheckFlags,
@@ -16,7 +14,12 @@ const {
   isCallExpression,
   isStringLiteral,
   isObjectProperty,
-} = require("../utils/index.js");
+} from "../utils/index.js";
+
+import doc from "../../document/index.js";
+
+import { ArgExpansionBailout } from "../../common/errors.js";
+import { isConciselyPrintedArray } from "./array.js";
 
 const {
   builders: {
@@ -30,10 +33,7 @@ const {
     breakParent,
   },
   utils: { willBreak },
-} = require("../../document/index.js");
-
-const { ArgExpansionBailout } = require("../../common/errors.js");
-const { isConciselyPrintedArray } = require("./array.js");
+} = doc;
 
 function printCallArguments(path, options, print) {
   const node = path.getValue();
@@ -303,4 +303,4 @@ function isTypeModuleObjectExpression(node) {
   );
 }
 
-module.exports = printCallArguments;
+export default printCallArguments;

src/language-js/print/call-expression.js

@@ -1,10 +1,6 @@
-"use strict";
-
-const {
-  builders: { join, group },
-} = require("../../document/index.js");
-const pathNeedsParens = require("../needs-parens.js");
-const {
+import doc from "../../document/index.js";
+import pathNeedsParens from "../needs-parens.js";
+import {
   getCallArguments,
   hasFlowAnnotationComment,
   isCallExpression,
@@ -13,13 +9,14 @@ const {
   isTemplateOnItsOwnLine,
   isTestCall,
   iterateCallArgumentsPath,
-} = require("../utils/index.js");
-const printMemberChain = require("./member-chain.js");
-const printCallArguments = require("./call-arguments.js");
+} from "../utils/index.js";
+import printMemberChain from "./member-chain.js";
+import printCallArguments from "./call-arguments.js";
+import { printOptionalToken, printFunctionTypeParameters } from "./misc.js";
+
 const {
-  printOptionalToken,
-  printFunctionTypeParameters,
-} = require("./misc.js");
+  builders: { join, group },
+} = doc;
 
 function printCallExpression(path, options, print) {
   const node = path.getValue();
@@ -128,4 +125,4 @@ function isCommonsJsOrAmdCall(node, parentNode) {
   return false;
 }
 
-module.exports = { printCallExpression };
+export { printCallExpression };

src/language-js/print/class.js

@@ -1,23 +1,17 @@
-"use strict";
+import { isNonEmptyArray, createGroupIdMapper } from "../../common/util.js";
+import { printComments, printDanglingComments } from "../../main/comments.js";
+import doc from "../../document/index.js";
+import { hasComment, CommentCheckFlags } from "../utils/index.js";
+import { getTypeParametersGroupId } from "./type-parameters.js";
+import { printMethod } from "./function.js";
+import { printOptionalToken, printTypeAnnotation } from "./misc.js";
+import { printPropertyKey } from "./property.js";
+import { printAssignment } from "./assignment.js";
+import { printClassMemberDecorators } from "./decorators.js";
 
-const {
-  isNonEmptyArray,
-  createGroupIdMapper,
-} = require("../../common/util.js");
-const {
-  printComments,
-  printDanglingComments,
-} = require("../../main/comments.js");
 const {
   builders: { join, line, hardline, softline, group, indent, ifBreak },
-} = require("../../document/index.js");
-const { hasComment, CommentCheckFlags } = require("../utils/index.js");
-const { getTypeParametersGroupId } = require("./type-parameters.js");
-const { printMethod } = require("./function.js");
-const { printOptionalToken, printTypeAnnotation } = require("./misc.js");
-const { printPropertyKey } = require("./property.js");
-const { printAssignment } = require("./assignment.js");
-const { printClassMemberDecorators } = require("./decorators.js");
+} = doc;
 
 function printClass(path, options, print) {
   const node = path.getValue();
@@ -226,7 +220,7 @@ function printClassProperty(path, options, print) {
   return [printAssignment(path, options, print, parts, " =", "value"), semi];
 }
 
-module.exports = {
+export {
   printClass,
   printClassMethod,
   printClassProperty,

src/language-js/print/comment.js

@@ -1,14 +1,14 @@
-"use strict";
+import { hasNewline } from "../../common/util.js";
+import doc from "../../document/index.js";
+
+import { isLineComment } from "../utils/index.js";
+import { locStart, locEnd } from "../loc.js";
+import isBlockComment from "../utils/is-block-comment.js";
 
-const { hasNewline } = require("../../common/util.js");
 const {
   builders: { join, hardline },
   utils: { replaceTextEndOfLine },
-} = require("../../document/index.js");
-
-const { isLineComment } = require("../utils/index.js");
-const { locStart, locEnd } = require("../loc.js");
-const isBlockComment = require("../utils/is-block-comment.js");
+} = doc;
 
 function printComment(commentPath, options) {
   const comment = commentPath.getValue();
@@ -77,4 +77,4 @@ function printIndentableBlockComment(comment) {
   ];
 }
 
-module.exports = { printComment };
+export { printComment };

src/language-js/print/decorators.js

@@ -1,11 +1,11 @@
-"use strict";
+import { isNonEmptyArray, hasNewline } from "../../common/util.js";
+import doc from "../../document/index.js";
+import { locStart, locEnd } from "../loc.js";
+import { getParentExportDeclaration } from "../utils/index.js";
 
-const { isNonEmptyArray, hasNewline } = require("../../common/util.js");
 const {
   builders: { line, hardline, join, breakParent, group },
-} = require("../../document/index.js");
-const { locStart, locEnd } = require("../loc.js");
-const { getParentExportDeclaration } = require("../utils/index.js");
+} = doc;
 
 function printClassMemberDecorators(path, options, print) {
   const node = path.getValue();
@@ -77,7 +77,7 @@ function hasDecoratorsBeforeExport(node) {
   );
 }
 
-module.exports = {
+export {
   printDecorators,
   printClassMemberDecorators,
   printDecoratorsBeforeExport,

src/language-js/print/flow.js

@@ -1,23 +1,19 @@
-"use strict";
-
 /** @typedef {import("../../document").Doc} Doc */
 
-const assert = require("assert");
-const { printDanglingComments } = require("../../main/comments.js");
-const { printString, printNumber } = require("../../common/util.js");
-const {
-  builders: { hardline, softline, group, indent },
-} = require("../../document/index.js");
-const {
+import assert from "assert";
+import { printDanglingComments } from "../../main/comments.js";
+import { printString, printNumber } from "../../common/util.js";
+import doc from "../../document/index.js";
+import {
   getParentExportDeclaration,
   isFunctionNotation,
   isGetterOrSetter,
   rawText,
   shouldPrintComma,
-} = require("../utils/index.js");
-const { locStart, locEnd } = require("../loc.js");
-const { printClass } = require("./class.js");
-const {
+} from "../utils/index.js";
+import { locStart, locEnd } from "../loc.js";
+import { printClass } from "./class.js";
+import {
   printOpaqueType,
   printTypeAlias,
   printIntersectionType,
@@ -25,24 +21,22 @@ const {
   printFunctionType,
   printTupleType,
   printIndexedAccessType,
-} = require("./type-annotation.js");
-const { printInterface } = require("./interface.js");
-const {
-  printTypeParameter,
-  printTypeParameters,
-} = require("./type-parameters.js");
-const {
-  printExportDeclaration,
-  printExportAllDeclaration,
-} = require("./module.js");
-const { printArrayItems } = require("./array.js");
-const { printObject } = require("./object.js");
-const { printPropertyKey } = require("./property.js");
-const {
+} from "./type-annotation.js";
+import { printInterface } from "./interface.js";
+import { printTypeParameter, printTypeParameters } from "./type-parameters.js";
+import { printExportDeclaration, printExportAllDeclaration } from "./module.js";
+import { printArrayItems } from "./array.js";
+import { printObject } from "./object.js";
+import { printPropertyKey } from "./property.js";
+import {
   printOptionalToken,
   printTypeAnnotation,
   printRestSpread,
-} = require("./misc.js");
+} from "./misc.js";
+
+const {
+  builders: { hardline, softline, group, indent },
+} = doc;
 
 function printFlow(path, options, print) {
   const node = path.getValue();
@@ -382,4 +376,4 @@ function printFlowDeclaration(path, printed) {
   return ["declare ", printed];
 }
 
-module.exports = { printFlow };
+export { printFlow };

src/language-js/print/function-parameters.js

@@ -1,12 +1,7 @@
-"use strict";
-
-const { getNextNonSpaceNonCommentCharacter } = require("../../common/util.js");
-const { printDanglingComments } = require("../../main/comments.js");
-const {
-  builders: { line, hardline, softline, group, indent, ifBreak },
-  utils: { removeLines, willBreak },
-} = require("../../document/index.js");
-const {
+import { getNextNonSpaceNonCommentCharacter } from "../../common/util.js";
+import { printDanglingComments } from "../../main/comments.js";
+import doc from "../../document/index.js";
+import {
   getFunctionParameters,
   iterateFunctionParametersPath,
   isSimpleType,
@@ -18,10 +13,15 @@ const {
   shouldPrintComma,
   hasComment,
   isNextLineEmpty,
-} = require("../utils/index.js");
-const { locEnd } = require("../loc.js");
-const { ArgExpansionBailout } = require("../../common/errors.js");
-const { printFunctionTypeParameters } = require("./misc.js");
+} from "../utils/index.js";
+import { locEnd } from "../loc.js";
+import { ArgExpansionBailout } from "../../common/errors.js";
+import { printFunctionTypeParameters } from "./misc.js";
+
+const {
+  builders: { line, hardline, softline, group, indent, ifBreak },
+  utils: { removeLines, willBreak },
+} = doc;
 
 function printFunctionParameters(
   path,
@@ -223,7 +223,7 @@ function shouldGroupFunctionParameters(functionNode, returnTypeDoc) {
   );
 }
 
-module.exports = {
+export {
   printFunctionParameters,
   shouldHugFunctionParameters,
   shouldGroupFunctionParameters,

src/language-js/print/function.js

@@ -1,31 +1,15 @@
-"use strict";
-
 /** @typedef {import("../../document/doc-builders").Doc} Doc */
 
-const assert = require("assert");
-const {
+import assert from "assert";
+import {
   printDanglingComments,
   printCommentsSeparately,
-} = require("../../main/comments.js");
-const getLast = require("../../utils/get-last.js");
-const {
-  getNextNonSpaceNonCommentCharacterIndex,
-} = require("../../common/util.js");
-const {
-  builders: {
-    line,
-    softline,
-    group,
-    indent,
-    ifBreak,
-    hardline,
-    join,
-    indentIfBreak,
-  },
-  utils: { removeLines, willBreak },
-} = require("../../document/index.js");
-const { ArgExpansionBailout } = require("../../common/errors.js");
-const {
+} from "../../main/comments.js";
+import getLast from "../../utils/get-last.js";
+import { getNextNonSpaceNonCommentCharacterIndex } from "../../common/util.js";
+import doc from "../../document/index.js";
+import { ArgExpansionBailout } from "../../common/errors.js";
+import {
   getFunctionParameters,
   hasLeadingOwnLineComment,
   isFlowAnnotationComment,
@@ -43,14 +27,28 @@ const {
   getCallArguments,
   hasNakedLeftSide,
   getLeftSide,
-} = require("../utils/index.js");
-const { locEnd } = require("../loc.js");
-const {
+} from "../utils/index.js";
+import { locEnd } from "../loc.js";
+import {
   printFunctionParameters,
   shouldGroupFunctionParameters,
-} = require("./function-parameters.js");
-const { printPropertyKey } = require("./property.js");
-const { printFunctionTypeParameters } = require("./misc.js");
+} from "./function-parameters.js";
+import { printPropertyKey } from "./property.js";
+import { printFunctionTypeParameters } from "./misc.js";
+
+const {
+  builders: {
+    line,
+    softline,
+    group,
+    indent,
+    ifBreak,
+    hardline,
+    join,
+    indentIfBreak,
+  },
+  utils: { removeLines, willBreak },
+} = doc;
 
 function printFunction(path, print, options, args) {
   const node = path.getValue();
@@ -528,7 +526,7 @@ function returnArgumentHasLeadingComment(options, argument) {
   return false;
 }
 
-module.exports = {
+export {
   printFunction,
   printArrowFunction,
   printMethod,

src/language-js/print/html-binding.js

@@ -1,8 +1,8 @@
-"use strict";
+import doc from "../../document/index.js";
 
 const {
   builders: { join, line, group, softline, indent },
-} = require("../../document/index.js");
+} = doc;
 
 function printHtmlBinding(path, options, print) {
   const node = path.getValue();
@@ -65,7 +65,4 @@ function isVueEventBindingExpression(node) {
   }
 }
 
-module.exports = {
-  isVueEventBindingExpression,
-  printHtmlBinding,
-};
+export { isVueEventBindingExpression, printHtmlBinding };

src/language-js/print/interface.js

@@ -1,16 +1,12 @@
-"use strict";
+import { isNonEmptyArray } from "../../common/util.js";
+import doc from "../../document/index.js";
+import { hasComment, identity, CommentCheckFlags } from "../utils/index.js";
+import { getTypeParametersGroupId } from "./type-parameters.js";
+import { printTypeScriptModifiers } from "./misc.js";
 
-const { isNonEmptyArray } = require("../../common/util.js");
 const {
   builders: { join, line, group, indent, ifBreak },
-} = require("../../document/index.js");
-const {
-  hasComment,
-  identity,
-  CommentCheckFlags,
-} = require("../utils/index.js");
-const { getTypeParametersGroupId } = require("./type-parameters.js");
-const { printTypeScriptModifiers } = require("./misc.js");
+} = doc;
 
 function printInterface(path, options, print) {
   const node = path.getValue();
@@ -74,4 +70,4 @@ function printInterface(path, options, print) {
   return group(parts);
 }
 
-module.exports = { printInterface };
+export { printInterface };

src/language-js/print/jsx.js

@@ -1,9 +1,21 @@
-"use strict";
+import { printComments, printDanglingComments } from "../../main/comments.js";
+import doc from "../../document/index.js";
+
+import { getLast, getPreferredQuote } from "../../common/util.js";
+import {
+  isJsxNode,
+  rawText,
+  isLiteral,
+  isCallExpression,
+  isStringLiteral,
+  isBinaryish,
+  hasComment,
+  CommentCheckFlags,
+  hasNodeIgnoreComment,
+} from "../utils/index.js";
+import pathNeedsParens from "../needs-parens.js";
+import { willPrintOwnComments } from "../comments.js";
 
-const {
-  printComments,
-  printDanglingComments,
-} = require("../../main/comments.js");
 const {
   builders: {
     line,
@@ -18,22 +30,7 @@ const {
     join,
   },
   utils: { willBreak },
-} = require("../../document/index.js");
-
-const { getLast, getPreferredQuote } = require("../../common/util.js");
-const {
-  isJsxNode,
-  rawText,
-  isLiteral,
-  isCallExpression,
-  isStringLiteral,
-  isBinaryish,
-  hasComment,
-  CommentCheckFlags,
-  hasNodeIgnoreComment,
-} = require("../utils/index.js");
-const pathNeedsParens = require("../needs-parens.js");
-const { willPrintOwnComments } = require("../comments.js");
+} = doc;
 
 const isEmptyStringOrAnyLine = (doc) =>
   doc === "" || doc === line || doc === hardline || doc === softline;
@@ -849,7 +846,4 @@ function hasJsxIgnoreComment(path) {
   );
 }
 
-module.exports = {
-  hasJsxIgnoreComment,
-  printJsx,
-};
+export { hasJsxIgnoreComment, printJsx };

src/language-js/print/literal.js

@@ -1,5 +1,4 @@
-"use strict";
-const { printString, printNumber } = require("../../common/util.js");
+import { printString, printNumber } from "../../common/util.js";
 
 function printLiteral(path, options /*, print*/) {
   const node = path.getNode();
@@ -57,6 +56,4 @@ function printRegex({ pattern, flags }) {
   return `/${pattern}/${flags}`;
 }
 
-module.exports = {
-  printLiteral,
-};
+export { printLiteral };

src/language-js/print/member-chain.js

@@ -1,13 +1,11 @@
-"use strict";
-
-const { printComments } = require("../../main/comments.js");
-const {
+import { printComments } from "../../main/comments.js";
+import {
   getLast,
   isNextLineEmptyAfterIndex,
   getNextNonSpaceNonCommentCharacterIndex,
-} = require("../../common/util.js");
-const pathNeedsParens = require("../needs-parens.js");
-const {
+} from "../../common/util.js";
+import pathNeedsParens from "../needs-parens.js";
+import {
   isCallExpression,
   isMemberExpression,
   isFunctionOrArrowExpression,
@@ -18,8 +16,17 @@ const {
   hasComment,
   CommentCheckFlags,
   isNextLineEmpty,
-} = require("../utils/index.js");
-const { locEnd } = require("../loc.js");
+} from "../utils/index.js";
+import { locEnd } from "../loc.js";
+
+import doc from "../../document/index.js";
+import printCallArguments from "./call-arguments.js";
+import { printMemberLookup } from "./member.js";
+import {
+  printOptionalToken,
+  printFunctionTypeParameters,
+  printBindExpressionCallee,
+} from "./misc.js";
 
 const {
   builders: {
@@ -32,14 +39,7 @@ const {
     label,
   },
   utils: { willBreak },
-} = require("../../document/index.js");
-const printCallArguments = require("./call-arguments.js");
-const { printMemberLookup } = require("./member.js");
-const {
-  printOptionalToken,
-  printFunctionTypeParameters,
-  printBindExpressionCallee,
-} = require("./misc.js");
+} = doc;
 
 // We detect calls on member expressions specially to format a
 // common pattern better. The pattern we are looking for is this:
@@ -407,4 +407,4 @@ function printMemberChain(path, options, print) {
   return label("member-chain", result);
 }
 
-module.exports = printMemberChain;
+export default printMemberChain;

src/language-js/print/member.js

@@ -1,14 +1,14 @@
-"use strict";
-
-const {
-  builders: { softline, group, indent, label },
-} = require("../../document/index.js");
-const {
+import doc from "../../document/index.js";
+import {
   isNumericLiteral,
   isMemberExpression,
   isCallExpression,
-} = require("../utils/index.js");
-const { printOptionalToken } = require("./misc.js");
+} from "../utils/index.js";
+import { printOptionalToken } from "./misc.js";
+
+const {
+  builders: { softline, group, indent, label },
+} = doc;
 
 function printMemberExpression(path, options, print) {
   const node = path.getValue();
@@ -68,4 +68,4 @@ function printMemberLookup(path, options, print) {
   return group([optional, "[", indent([softline, property]), softline, "]"]);
 }
 
-module.exports = { printMemberExpression, printMemberLookup };
+export { printMemberExpression, printMemberLookup };

src/language-js/print/misc.js

@@ -1,10 +1,10 @@
-"use strict";
+import { isNonEmptyArray } from "../../common/util.js";
+import doc from "../../document/index.js";
+import { isFlowAnnotationComment } from "../utils/index.js";
 
-const { isNonEmptyArray } = require("../../common/util.js");
 const {
   builders: { indent, join, line },
-} = require("../../document/index.js");
-const { isFlowAnnotationComment } = require("../utils/index.js");
+} = doc;
 
 function printOptionalToken(path) {
   const node = path.getValue();
@@ -90,7 +90,7 @@ function printRestSpread(path, options, print) {
   return ["...", print("argument"), printTypeAnnotation(path, options, print)];
 }
 
-module.exports = {
+export {
   printOptionalToken,
   printFunctionTypeParameters,
   printBindExpressionCallee,

src/language-js/print/module.js

@@ -1,24 +1,24 @@
-"use strict";
+import { isNonEmptyArray } from "../../common/util.js";
+import doc from "../../document/index.js";
+import { printDanglingComments } from "../../main/comments.js";
 
-const { isNonEmptyArray } = require("../../common/util.js");
-const {
-  builders: { softline, group, indent, join, line, ifBreak, hardline },
-} = require("../../document/index.js");
-const { printDanglingComments } = require("../../main/comments.js");
-
-const {
+import {
   hasComment,
   CommentCheckFlags,
   shouldPrintComma,
   needsHardlineAfterDanglingComment,
   isStringLiteral,
   rawText,
-} = require("../utils/index.js");
-const { locStart, hasSameLoc } = require("../loc.js");
-const {
+} from "../utils/index.js";
+import { locStart, hasSameLoc } from "../loc.js";
+import {
   hasDecoratorsBeforeExport,
   printDecoratorsBeforeExport,
-} = require("./decorators.js");
+} from "./decorators.js";
+
+const {
+  builders: { softline, group, indent, join, line, ifBreak, hardline },
+} = doc;
 
 /**
  * @typedef {import("../../document").Doc} Doc
@@ -354,7 +354,7 @@ function isShorthandSpecifier(specifier) {
   }
 }
 
-module.exports = {
+export {
   printImportDeclaration,
   printExportDeclaration,
   printExportAllDeclaration,

src/language-js/print/object.js

@@ -1,28 +1,28 @@
-"use strict";
-
-const { printDanglingComments } = require("../../main/comments.js");
-const {
-  builders: { line, softline, group, indent, ifBreak, hardline },
-} = require("../../document/index.js");
-const {
+import { printDanglingComments } from "../../main/comments.js";
+import doc from "../../document/index.js";
+import {
   getLast,
   hasNewlineInRange,
   hasNewline,
   isNonEmptyArray,
-} = require("../../common/util.js");
-const {
+} from "../../common/util.js";
+import {
   shouldPrintComma,
   hasComment,
   getComments,
   CommentCheckFlags,
   isNextLineEmpty,
-} = require("../utils/index.js");
-const { locStart, locEnd } = require("../loc.js");
+} from "../utils/index.js";
+import { locStart, locEnd } from "../loc.js";
 
-const { printOptionalToken, printTypeAnnotation } = require("./misc.js");
-const { shouldHugFunctionParameters } = require("./function-parameters.js");
-const { shouldHugType } = require("./type-annotation.js");
-const { printHardlineAfterHeritage } = require("./class.js");
+import { printOptionalToken, printTypeAnnotation } from "./misc.js";
+import { shouldHugFunctionParameters } from "./function-parameters.js";
+import { shouldHugType } from "./type-annotation.js";
+import { printHardlineAfterHeritage } from "./class.js";
+
+const {
+  builders: { line, softline, group, indent, ifBreak, hardline },
+} = doc;
 
 /** @typedef {import("../../document").Doc} Doc */
 
@@ -243,4 +243,4 @@ function printObject(path, options, print) {
   return group(content, { shouldBreak });
 }
 
-module.exports = { printObject };
+export { printObject };

src/language-js/print/property.js

@@ -1,15 +1,13 @@
-"use strict";
-
-const { printComments } = require("../../main/comments.js");
-const { printString, printNumber } = require("../../common/util.js");
-const {
+import { printComments } from "../../main/comments.js";
+import { printString, printNumber } from "../../common/util.js";
+import {
   isNumericLiteral,
   isSimpleNumber,
   isStringLiteral,
   isStringPropSafeToUnquote,
   rawText,
-} = require("../utils/index.js");
-const { printAssignment } = require("./assignment.js");
+} from "../utils/index.js";
+import { printAssignment } from "./assignment.js";
 
 const needsQuoteProps = new WeakMap();
 
@@ -105,4 +103,4 @@ function printProperty(path, options, print) {
   );
 }
 
-module.exports = { printProperty, printPropertyKey };
+export { printProperty, printPropertyKey };

src/language-js/print/statement.js

@@ -1,10 +1,6 @@
-"use strict";
-
-const {
-  builders: { hardline },
-} = require("../../document/index.js");
-const pathNeedsParens = require("../needs-parens.js");
-const {
+import doc from "../../document/index.js";
+import pathNeedsParens from "../needs-parens.js";
+import {
   getLeftSidePathName,
   hasNakedLeftSide,
   isJsxNode,
@@ -12,8 +8,12 @@ const {
   hasComment,
   CommentCheckFlags,
   isNextLineEmpty,
-} = require("../utils/index.js");
-const { shouldPrintParamsWithoutParens } = require("./function.js");
+} from "../utils/index.js";
+import { shouldPrintParamsWithoutParens } from "./function.js";
+
+const {
+  builders: { hardline },
+} = doc;
 
 /**
  * @typedef {import("../../document").Doc} Doc
@@ -245,7 +245,4 @@ function shouldPrintSemicolonAfterClassProperty(node, nextNode) {
   return false;
 }
 
-module.exports = {
-  printBody,
-  printSwitchCaseConsequent,
-};
+export { printBody, printSwitchCaseConsequent };

src/language-js/print/template-literal.js

@@ -1,7 +1,14 @@
-"use strict";
+import getLast from "../../utils/get-last.js";
+import { getStringWidth, getIndentSize } from "../../common/util.js";
+import doc from "../../document/index.js";
+import {
+  isBinaryish,
+  isJestEachTemplateLiteral,
+  isSimpleTemplateLiteral,
+  hasComment,
+  isMemberExpression,
+} from "../utils/index.js";
 
-const getLast = require("../../utils/get-last.js");
-const { getStringWidth, getIndentSize } = require("../../common/util.js");
 const {
   builders: {
     join,
@@ -15,14 +22,7 @@ const {
   },
   printer: { printDocToString },
   utils: { mapDoc },
-} = require("../../document/index.js");
-const {
-  isBinaryish,
-  isJestEachTemplateLiteral,
-  isSimpleTemplateLiteral,
-  hasComment,
-  isMemberExpression,
-} = require("../utils/index.js");
+} = doc;
 
 function printTemplateLiteral(path, print, options) {
   const node = path.getValue();
@@ -232,7 +232,7 @@ function uncookTemplateElementValue(cookedValue) {
   return cookedValue.replace(/([\\`]|\${)/g, "\\$1");
 }
 
-module.exports = {
+export {
   printTemplateLiteral,
   printTemplateExpressions,
   escapeTemplateCharacters,

src/language-js/print/ternary.js

@@ -1,14 +1,14 @@
-"use strict";
-
-const { hasNewlineInRange } = require("../../common/util.js");
-const {
+import { hasNewlineInRange } from "../../common/util.js";
+import {
   isJsxNode,
   getComments,
   isCallExpression,
   isMemberExpression,
-} = require("../utils/index.js");
-const { locStart, locEnd } = require("../loc.js");
-const isBlockComment = require("../utils/is-block-comment.js");
+} from "../utils/index.js";
+import { locStart, locEnd } from "../loc.js";
+import isBlockComment from "../utils/is-block-comment.js";
+import doc from "../../document/index.js";
+
 const {
   builders: {
     line,
@@ -20,7 +20,7 @@ const {
     dedent,
     breakParent,
   },
-} = require("../../document/index.js");
+} = doc;
 
 /**
  * @typedef {import("../../document").Doc} Doc
@@ -352,4 +352,4 @@ function printTernary(path, options, print) {
     : result;
 }
 
-module.exports = { printTernary };
+export { printTernary };

src/language-js/print/type-annotation.js

@@ -1,28 +1,25 @@
-"use strict";
-
-const {
-  printComments,
-  printDanglingComments,
-} = require("../../main/comments.js");
-const { getLast, isNonEmptyArray } = require("../../common/util.js");
-const {
-  builders: { group, join, line, softline, indent, align, ifBreak },
-} = require("../../document/index.js");
-const pathNeedsParens = require("../needs-parens.js");
-const { locStart } = require("../loc.js");
-const {
+import { printComments, printDanglingComments } from "../../main/comments.js";
+import { getLast, isNonEmptyArray } from "../../common/util.js";
+import doc from "../../document/index.js";
+import pathNeedsParens from "../needs-parens.js";
+import { locStart } from "../loc.js";
+import {
   isSimpleType,
   isObjectType,
   hasLeadingOwnLineComment,
   isObjectTypePropertyAFunction,
   shouldPrintComma,
-} = require("../utils/index.js");
-const { printAssignment } = require("./assignment.js");
-const {
+} from "../utils/index.js";
+import { printAssignment } from "./assignment.js";
+import {
   printFunctionParameters,
   shouldGroupFunctionParameters,
-} = require("./function-parameters.js");
-const { printArrayItems } = require("./array.js");
+} from "./function-parameters.js";
+import { printArrayItems } from "./array.js";
+
+const {
+  builders: { group, join, line, softline, indent, align, ifBreak },
+} = doc;
 
 function shouldHugType(node) {
   if (isSimpleType(node) || isObjectType(node)) {
@@ -314,7 +311,7 @@ function printIndexedAccessType(path, options, print) {
   return [print("objectType"), leftDelimiter, print("indexType"), "]"];
 }
 
-module.exports = {
+export {
   printOpaqueType,
   printTypeAlias,
   printIntersectionType,

src/language-js/print/type-parameters.js

@@ -1,10 +1,6 @@
-"use strict";
-
-const { printDanglingComments } = require("../../main/comments.js");
-const {
-  builders: { join, line, hardline, softline, group, indent, ifBreak },
-} = require("../../document/index.js");
-const {
+import { printDanglingComments } from "../../main/comments.js";
+import doc from "../../document/index.js";
+import {
   isTestCall,
   hasComment,
   CommentCheckFlags,
@@ -12,10 +8,14 @@ const {
   shouldPrintComma,
   getFunctionParameters,
   isObjectType,
-} = require("../utils/index.js");
-const { createGroupIdMapper } = require("../../common/util.js");
-const { shouldHugType } = require("./type-annotation.js");
-const { isArrowFunctionVariableDeclarator } = require("./assignment.js");
+} from "../utils/index.js";
+import { createGroupIdMapper } from "../../common/util.js";
+import { shouldHugType } from "./type-annotation.js";
+import { isArrowFunctionVariableDeclarator } from "./assignment.js";
+
+const {
+  builders: { join, line, hardline, softline, group, indent, ifBreak },
+} = doc;
 
 const getTypeParametersGroupId = createGroupIdMapper("typeParameters");
 
@@ -144,8 +144,4 @@ function printTypeParameter(path, options, print) {
   return parts;
 }
 
-module.exports = {
-  printTypeParameter,
-  printTypeParameters,
-  getTypeParametersGroupId,
-};
+export { printTypeParameter, printTypeParameters, getTypeParametersGroupId };

src/language-js/print/typescript.js

@@ -1,7 +1,40 @@
-"use strict";
+import { printDanglingComments } from "../../main/comments.js";
+import { hasNewlineInRange } from "../../common/util.js";
+import doc from "../../document/index.js";
+import {
+  isLiteral,
+  getTypeScriptMappedTypeModifier,
+  shouldPrintComma,
+  isCallExpression,
+  isMemberExpression,
+} from "../utils/index.js";
+import isTsKeywordType from "../utils/is-ts-keyword-type.js";
+import { locStart, locEnd } from "../loc.js";
+
+import { printOptionalToken, printTypeScriptModifiers } from "./misc.js";
+import { printTernary } from "./ternary.js";
+import {
+  printFunctionParameters,
+  shouldGroupFunctionParameters,
+} from "./function-parameters.js";
+import { printTemplateLiteral } from "./template-literal.js";
+import { printArrayItems } from "./array.js";
+import { printObject } from "./object.js";
+import { printClassProperty, printClassMethod } from "./class.js";
+import { printTypeParameter, printTypeParameters } from "./type-parameters.js";
+import { printPropertyKey } from "./property.js";
+import { printFunction, printMethodInternal } from "./function.js";
+import { printInterface } from "./interface.js";
+import { printBlock } from "./block.js";
+import {
+  printTypeAlias,
+  printIntersectionType,
+  printUnionType,
+  printFunctionType,
+  printTupleType,
+  printIndexedAccessType,
+} from "./type-annotation.js";
 
-const { printDanglingComments } = require("../../main/comments.js");
-const { hasNewlineInRange } = require("../../common/util.js");
 const {
   builders: {
     join,
@@ -13,43 +46,7 @@ const {
     conditionalGroup,
     ifBreak,
   },
-} = require("../../document/index.js");
-const {
-  isLiteral,
-  getTypeScriptMappedTypeModifier,
-  shouldPrintComma,
-  isCallExpression,
-  isMemberExpression,
-} = require("../utils/index.js");
-const isTsKeywordType = require("../utils/is-ts-keyword-type.js");
-const { locStart, locEnd } = require("../loc.js");
-
-const { printOptionalToken, printTypeScriptModifiers } = require("./misc.js");
-const { printTernary } = require("./ternary.js");
-const {
-  printFunctionParameters,
-  shouldGroupFunctionParameters,
-} = require("./function-parameters.js");
-const { printTemplateLiteral } = require("./template-literal.js");
-const { printArrayItems } = require("./array.js");
-const { printObject } = require("./object.js");
-const { printClassProperty, printClassMethod } = require("./class.js");
-const {
-  printTypeParameter,
-  printTypeParameters,
-} = require("./type-parameters.js");
-const { printPropertyKey } = require("./property.js");
-const { printFunction, printMethodInternal } = require("./function.js");
-const { printInterface } = require("./interface.js");
-const { printBlock } = require("./block.js");
-const {
-  printTypeAlias,
-  printIntersectionType,
-  printUnionType,
-  printFunctionType,
-  printTupleType,
-  printIndexedAccessType,
-} = require("./type-annotation.js");
+} = doc;
 
 function printTypescript(path, options, print) {
   const node = path.getValue();
@@ -528,4 +525,4 @@ function printTypescript(path, options, print) {
   }
 }
 
-module.exports = { printTypescript };
+export { printTypescript };

src/language-js/printer-estree-json.js

@@ -1,9 +1,9 @@
-"use strict";
+import doc from "../document/index.js";
+import preprocess from "./print-preprocess.js";
 
 const {
   builders: { hardline, indent, join },
-} = require("../document/index.js");
-const preprocess = require("./print-preprocess.js");
+} = doc;
 
 function genericPrint(path, options, print) {
   const node = path.getValue();
@@ -109,8 +109,10 @@ function clean(node, newNode /*, parent*/) {
 
 clean.ignoredProperties = ignoredProperties;
 
-module.exports = {
+const printer = {
   preprocess,
   print: genericPrint,
   massageAstNode: clean,
 };
+
+export default printer;

src/language-js/printer-estree.js

@@ -1,21 +1,16 @@
-"use strict";
-
 /** @typedef {import("../document").Doc} Doc */
 
 // TODO(azz): anything that imports from main shouldn't be in a `language-*` dir.
-const { printDanglingComments } = require("../main/comments.js");
-const { hasNewline } = require("../common/util.js");
-const {
-  builders: { join, line, hardline, softline, group, indent },
-  utils: { replaceTextEndOfLine },
-} = require("../document/index.js");
-const embed = require("./embed.js");
-const clean = require("./clean.js");
-const { insertPragma } = require("./pragma.js");
-const handleComments = require("./comments.js");
-const pathNeedsParens = require("./needs-parens.js");
-const preprocess = require("./print-preprocess.js");
-const {
+import { printDanglingComments } from "../main/comments.js";
+import { hasNewline } from "../common/util.js";
+import doc from "../document/index.js";
+import embed from "./embed.js";
+import clean from "./clean.js";
+import { insertPragma } from "./pragma.js";
+import * as handleComments from "./comments.js";
+import pathNeedsParens from "./needs-parens.js";
+import preprocess from "./print-preprocess.js";
+import {
   hasFlowShorthandAnnotationComment,
   hasComment,
   CommentCheckFlags,
@@ -28,60 +23,65 @@ const {
   isCallExpression,
   isMemberExpression,
   markerForIfWithoutBlockAndSameLineComment,
-} = require("./utils/index.js");
-const { locStart, locEnd } = require("./loc.js");
-const isBlockComment = require("./utils/is-block-comment.js");
+} from "./utils/index.js";
+import { locStart, locEnd } from "./loc.js";
+import isBlockComment from "./utils/is-block-comment.js";
 
-const {
+import {
   printHtmlBinding,
   isVueEventBindingExpression,
-} = require("./print/html-binding.js");
-const { printAngular } = require("./print/angular.js");
-const { printJsx, hasJsxIgnoreComment } = require("./print/jsx.js");
-const { printFlow } = require("./print/flow.js");
-const { printTypescript } = require("./print/typescript.js");
-const {
+} from "./print/html-binding.js";
+import { printAngular } from "./print/angular.js";
+import { printJsx, hasJsxIgnoreComment } from "./print/jsx.js";
+import { printFlow } from "./print/flow.js";
+import { printTypescript } from "./print/typescript.js";
+import {
   printOptionalToken,
   printBindExpressionCallee,
   printTypeAnnotation,
   adjustClause,
   printRestSpread,
-} = require("./print/misc.js");
-const {
+} from "./print/misc.js";
+import {
   printImportDeclaration,
   printExportDeclaration,
   printExportAllDeclaration,
   printModuleSpecifier,
-} = require("./print/module.js");
-const { printTernary } = require("./print/ternary.js");
-const { printTemplateLiteral } = require("./print/template-literal.js");
-const { printArray } = require("./print/array.js");
-const { printObject } = require("./print/object.js");
-const {
+} from "./print/module.js";
+import { printTernary } from "./print/ternary.js";
+import { printTemplateLiteral } from "./print/template-literal.js";
+import { printArray } from "./print/array.js";
+import { printObject } from "./print/object.js";
+import {
   printClass,
   printClassMethod,
   printClassProperty,
-} = require("./print/class.js");
-const { printProperty } = require("./print/property.js");
-const {
+} from "./print/class.js";
+import { printProperty } from "./print/property.js";
+import {
   printFunction,
   printArrowFunction,
   printMethod,
   printReturnStatement,
   printThrowStatement,
-} = require("./print/function.js");
-const { printCallExpression } = require("./print/call-expression.js");
-const {
+} from "./print/function.js";
+import { printCallExpression } from "./print/call-expression.js";
+import {
   printVariableDeclarator,
   printAssignmentExpression,
-} = require("./print/assignment.js");
-const { printBinaryishExpression } = require("./print/binaryish.js");
-const { printSwitchCaseConsequent } = require("./print/statement.js");
-const { printMemberExpression } = require("./print/member.js");
-const { printBlock, printBlockBody } = require("./print/block.js");
-const { printComment } = require("./print/comment.js");
-const { printLiteral } = require("./print/literal.js");
-const { printDecorators } = require("./print/decorators.js");
+} from "./print/assignment.js";
+import { printBinaryishExpression } from "./print/binaryish.js";
+import { printSwitchCaseConsequent } from "./print/statement.js";
+import { printMemberExpression } from "./print/member.js";
+import { printBlock, printBlockBody } from "./print/block.js";
+import { printComment } from "./print/comment.js";
+import { printLiteral } from "./print/literal.js";
+import { printDecorators } from "./print/decorators.js";
+
+const {
+  builders: { join, line, hardline, softline, group, indent },
+  utils: { replaceTextEndOfLine },
+} = doc;
 
 function genericPrint(path, options, print, args) {
   const printed = printPathNoParens(path, options, print, args);
@@ -835,7 +835,7 @@ function canAttachComment(node) {
   );
 }
 
-module.exports = {
+const printer = {
   preprocess,
   print: genericPrint,
   embed,
@@ -857,3 +857,5 @@ module.exports = {
   },
   getCommentChildNodes: handleComments.getCommentChildNodes,
 };
+
+export default printer;

src/language-js/utils/get-shebang.js

@@ -1,5 +1,3 @@
-"use strict";
-
 function getShebang(text) {
   if (!text.startsWith("#!")) {
     return "";
@@ -11,4 +9,4 @@ function getShebang(text) {
   return text.slice(0, index);
 }
 
-module.exports = getShebang;
+export default getShebang;

src/language-js/utils/index.js

@@ -1,16 +1,16 @@
-"use strict";
-
-const isIdentifierName = require("esutils").keyword.isIdentifierNameES5;
-const {
+import esutils from "esutils";
+import {
   getLast,
   hasNewline,
   skipWhitespace,
   isNonEmptyArray,
   isNextLineEmptyAfterIndex,
   getStringWidth,
-} = require("../../common/util.js");
-const { locStart, locEnd, hasSameLocStart } = require("../loc.js");
-const isBlockComment = require("./is-block-comment.js");
+} from "../../common/util.js";
+import { locStart, locEnd, hasSameLocStart } from "../loc.js";
+import isBlockComment from "./is-block-comment.js";
+
+const isIdentifierName = esutils.keyword.isIdentifierNameES5;
 
 /**
  * @typedef {import("../types/estree").Node} Node
@@ -1311,7 +1311,7 @@ const markerForIfWithoutBlockAndSameLineComment = Symbol(
   "ifWithoutBlockAndSameLineComment"
 );
 
-module.exports = {
+export {
   getFunctionParameters,
   iterateFunctionParametersPath,
   getCallArguments,

src/language-js/utils/is-block-comment.js

@@ -1,5 +1,3 @@
-"use strict";
-
 /**
  * @typedef {import("../types/estree").Comment} Comment
  */
@@ -17,4 +15,4 @@ function isBlockComment(comment) {
   );
 }
 
-module.exports = isBlockComment;
+export default isBlockComment;

src/language-js/utils/is-ts-keyword-type.js

@@ -1,4 +1,3 @@
-"use strict";
 /**
  * @returns {boolean}
  */
@@ -6,4 +5,4 @@ function isTsKeywordType({ type }) {
   return type.startsWith("TS") && type.endsWith("Keyword");
 }
 
-module.exports = isTsKeywordType;
+export default isTsKeywordType;

src/language-js/utils/is-type-cast-comment.js

@@ -1,6 +1,4 @@
-"use strict";
-
-const isBlockComment = require("./is-block-comment.js");
+import isBlockComment from "./is-block-comment.js";
 
 /**
  * @typedef {import("../types/estree").Comment} Comment
@@ -21,4 +19,4 @@ function isTypeCastComment(comment) {
   );
 }
 
-module.exports = isTypeCastComment;
+export default isTypeCastComment;

src/languages.js

@@ -1,4 +1,5 @@
 import { createRequire } from "module";
+import js from "./language-js/index.js";
 import css from "./language-css/index.js";
 import handlebars from "./language-handlebars/index.js";
 import graphql from "./language-graphql/index.js";
@@ -10,7 +11,7 @@ const require = createRequire(import.meta.url);
 // We need to list the parsers and getters so we can load them only when necessary.
 const languages = [
   // JS
-  require("./language-js/index.js"),
+  js,
   // CSS
   css,
   // Handlebars

src/main/parser.js

@@ -2,7 +2,8 @@
 
 const path = require("path");
 const { ConfigError } = require("../common/errors.js");
-const jsLoc = require("../language-js/loc.js");
+// TODO: Use esm version
+const jsLoc = require("../language-js/loc.cjs");
 
 const { locStart, locEnd } = jsLoc;