Build: es module proof of concept DO NOT MERGE :) fixes #457

espree.js

@@ -56,13 +56,15 @@
  */
 /* eslint no-undefined:0, no-use-before-define: 0 */
 
-"use strict";
 
-const acorn = require("acorn");
-const jsx = require("acorn-jsx");
-const astNodeTypes = require("./lib/ast-node-types");
-const espree = require("./lib/espree");
-const { getLatestEcmaVersion, getSupportedEcmaVersions } = require("./lib/options");
+import * as acorn    from "acorn";
+import jsx           from "acorn-jsx";
+import astNodeTypes  from "./lib/ast-node-types.js";
+import espree        from "./lib/espree.js";
+import { getLatestEcmaVersion, getSupportedEcmaVersions } from "./lib/options.js";
+import espreeVersion from './lib/version.js';
+import visitorKeys   from 'eslint-visitor-keys';
+
 
 // To initialize lazily.
 const parsers = {
@@ -106,7 +108,7 @@ const parsers = {
  * @throws {SyntaxError} If the input code is invalid.
  * @private
  */
-function tokenize(code, options) {
+export function tokenize(code, options) {
     const Parser = parsers.get(options);
 
     // Ensure to collect tokens.
@@ -128,7 +130,7 @@ function tokenize(code, options) {
  * @returns {ASTNode} The "Program" AST node.
  * @throws {SyntaxError} If the input code is invalid.
  */
-function parse(code, options) {
+export function parse(code, options) {
     const Parser = parsers.get(options);
 
     return new Parser(options, code).parse();
@@ -138,15 +140,12 @@ function parse(code, options) {
 // Public
 //------------------------------------------------------------------------------
 
-exports.version = require("./package.json").version;
-
-exports.tokenize = tokenize;
+export const version = espreeVersion;
 
-exports.parse = parse;
 
 // Deep copy.
 /* istanbul ignore next */
-exports.Syntax = (function() {
+export const Syntax = (function() {
     let name,
         types = {};
 
@@ -168,10 +167,11 @@ exports.Syntax = (function() {
 }());
 
 /* istanbul ignore next */
-exports.VisitorKeys = (function() {
-    return require("eslint-visitor-keys").KEYS;
+export const VisitorKeys = (function() {
+    //return require("eslint-visitor-keys").KEYS;
+    return visitorKeys.KEYS;
 }());
 
-exports.latestEcmaVersion = getLatestEcmaVersion();
+export const latestEcmaVersion = getLatestEcmaVersion();
 
-exports.supportedEcmaVersions = getSupportedEcmaVersions();
+export const supportedEcmaVersions = getSupportedEcmaVersions();

lib/ast-node-types.js

@@ -3,8 +3,6 @@
  * @author Nicholas C. Zakas
  */
 
-"use strict";
-
 //------------------------------------------------------------------------------
 // Requirements
 //------------------------------------------------------------------------------
@@ -15,7 +13,7 @@
 // Public
 //------------------------------------------------------------------------------
 
-module.exports = {
+export default {
     AssignmentExpression: "AssignmentExpression",
     AssignmentPattern: "AssignmentPattern",
     ArrayExpression: "ArrayExpression",

lib/espree.js

@@ -1,8 +1,7 @@
-"use strict";
 
 /* eslint-disable no-param-reassign*/
-const TokenTranslator = require("./token-translator");
-const { normalizeOptions } = require("./options");
+import TokenTranslator from "./token-translator.js";
+import { normalizeOptions } from "./options.js";
 
 const STATE = Symbol("espree's internal state");
 const ESPRIMA_FINISH_NODE = Symbol("espree's esprimaFinishNode");
@@ -41,7 +40,7 @@ function convertAcornCommentToEsprimaComment(block, text, start, end, startLoc,
     return comment;
 }
 
-module.exports = () => Parser => {
+export default () => Parser => {
     const tokTypes = Object.assign({}, Parser.acorn.tokTypes);
 
     if (Parser.acornJsx) {

lib/features.js

@@ -4,8 +4,6 @@
  * @author Nicholas C. Zakas
  */
 
-"use strict";
-
 //------------------------------------------------------------------------------
 // Requirements
 //------------------------------------------------------------------------------
@@ -16,7 +14,7 @@
 // Public
 //------------------------------------------------------------------------------
 
-module.exports = {
+export default {
 
     // React JSX parsing
     jsx: false,

lib/options.js

@@ -3,8 +3,6 @@
  * @author Kai Cataldo
  */
 
-"use strict";
-
 //------------------------------------------------------------------------------
 // Helpers
 //------------------------------------------------------------------------------
@@ -67,7 +65,7 @@ function normalizeSourceType(sourceType = "script") {
  * @throws {Error} throw an error if found invalid option.
  * @returns {Object} normalized options
  */
-function normalizeOptions(options) {
+export function normalizeOptions(options) {
     const ecmaVersion = normalizeEcmaVersion(options.ecmaVersion);
     const sourceType = normalizeSourceType(options.sourceType);
     const ranges = options.range === true;
@@ -83,24 +81,14 @@ function normalizeOptions(options) {
  * Get the latest ECMAScript version supported by Espree.
  * @returns {number} The latest ECMAScript version.
  */
-function getLatestEcmaVersion() {
+export function getLatestEcmaVersion() {
     return SUPPORTED_VERSIONS[SUPPORTED_VERSIONS.length - 1];
 }
 
 /**
  * Get the list of ECMAScript versions supported by Espree.
  * @returns {number[]} An array containing the supported ECMAScript versions.
  */
-function getSupportedEcmaVersions() {
+export function getSupportedEcmaVersions() {
     return [...SUPPORTED_VERSIONS];
 }
-
-//------------------------------------------------------------------------------
-// Public
-//------------------------------------------------------------------------------
-
-module.exports = {
-    normalizeOptions,
-    getLatestEcmaVersion,
-    getSupportedEcmaVersions
-};

lib/token-translator.js

@@ -4,8 +4,6 @@
  */
 /* eslint no-underscore-dangle: 0 */
 
-"use strict";
-
 //------------------------------------------------------------------------------
 // Requirements
 //------------------------------------------------------------------------------
@@ -260,4 +258,4 @@ TokenTranslator.prototype = {
 // Public
 //------------------------------------------------------------------------------
 
-module.exports = TokenTranslator;
+export default TokenTranslator;

lib/version.js

@@ -0,0 +1 @@
+export default version = '7.3.0'

lib/visitor-keys.js

@@ -25,7 +25,6 @@
  * SOFTWARE.
  */
 
-"use strict";
 
 //------------------------------------------------------------------------------
 // Requirements
@@ -37,7 +36,7 @@
 // Public
 //------------------------------------------------------------------------------
 
-module.exports = {
+export default {
 
     // ECMAScript
     AssignmentExpression: ["left", "right"],

package.json

@@ -3,7 +3,12 @@
   "description": "An Esprima-compatible JavaScript parser built on Acorn",
   "author": "Nicholas C. Zakas <nicholas+npm@nczconsulting.com>",
   "homepage": "https://github.com/eslint/espree",
-  "main": "espree.js",
+  "main": "dist/espree.cjs",
+  "module": "espree.js",
+  "exports": {
+    "import": "espree.js",
+    "require": "./dist/espree.cjs"
+  },
   "version": "7.3.0",
   "files": [
     "lib",
@@ -18,11 +23,14 @@
   },
   "license": "BSD-2-Clause",
   "dependencies": {
-    "acorn": "^7.4.0",
+    "acorn": "^8.0.4",
     "acorn-jsx": "^5.2.0",
     "eslint-visitor-keys": "^1.3.0"
   },
   "devDependencies": {
+    "@rollup/plugin-commonjs": "^16.0.0",
+    "@rollup/plugin-json": "^4.1.0",
+    "@rollup/plugin-node-resolve": "^10.0.0",
     "browserify": "^16.5.0",
     "chai": "^4.2.0",
     "eslint": "^6.0.1",
@@ -36,6 +44,7 @@
     "mocha": "^6.2.0",
     "nyc": "^14.1.1",
     "regenerate": "^1.4.0",
+    "rollup": "^2.33.3",
     "shelljs": "^0.3.0",
     "shelljs-nodecli": "^0.1.1",
     "unicode-6.3.0": "^0.7.5"
@@ -54,6 +63,7 @@
     "lint": "node Makefile.js lint",
     "fixlint": "node Makefile.js lint --fix",
     "sync-docs": "node Makefile.js docs",
+    "rollup": "rollup -c rollup.config.js",
     "browserify": "node Makefile.js browserify",
     "generate-release": "eslint-generate-release",
     "generate-alpharelease": "eslint-generate-prerelease alpha",

rollup.config.js

@@ -0,0 +1,31 @@
+import commonjs from '@rollup/plugin-commonjs';
+import resolve  from '@rollup/plugin-node-resolve';
+import json     from '@rollup/plugin-json';
+import fs       from 'fs';
+
+
+const pkg = JSON.parse(fs.readFileSync('./package.json', 'utf8'));
+fs.writeFileSync('lib/version.js', `export default version = '${pkg.version}'`);
+
+export default [
+  {
+    input: "espree.js",
+    output: {
+      file: "dist/espree.js",
+      format: "umd",
+      name: "espree",
+      sourcemap: true
+    },
+    plugins: [ commonjs(), resolve(), json() ]
+  },
+  {
+    input: "espree.js",
+    external: ["acorn", "acorn-jsx", "eslint-visitor-keys"],
+    output: {
+      file: "dist/espree.cjs",
+      format: "cjs",
+      sourcemap: true
+    },
+    plugins: [ ]
+  }
+]

tests/lib/acorn-after-espree.js

@@ -19,10 +19,10 @@ const acorn = require("acorn"),
 
 describe("acorn", () => {
     it("acorn.parse() should work after espree was loaded.", () => {
-        const before = acorn.parse("var foo = bar /*world*/;");
+        const before = acorn.parse("var foo = bar /*world*/;", { ecmaVersion: 5 });
 
         require("../../espree");
-        const after = acorn.parse("var foo = bar /*world*/;");
+        const after = acorn.parse("var foo = bar /*world*/;", { ecmaVersion: 5 });
 
         assert.deepStrictEqual(after, before);
     });