A Babel plugin to inject imports to core-js@2 polyfills. 

A Babel plugin to inject imports to core-js@2 polyfills

nicolo-ribaudo

babel-plugin-polyfill-corejs2

var _corejs2BuiltIns = _interopRequireDefault(require("@babel/compat-data/corejs2-built-ins"));

var _builtInDefinitions = require("./built-in-definitions");

var _addPlatformSpecificPolyfills = _interopRequireDefault(require("./add-platform-specific-polyfills"));

var _helperDefinePolyfillProvider = _interopRequireDefault(require("@babel/helper-define-polyfill-provider"));

var _babel = _interopRequireWildcard(require("@babel/core"));

function _getRequireWildcardCache(nodeInterop) { if (typeof WeakMap !== "function") return null; var cacheBabelInterop = new WeakMap(); var cacheNodeInterop = new WeakMap(); return (_getRequireWildcardCache = function (nodeInterop) { return nodeInterop ? cacheNodeInterop : cacheBabelInterop; })(nodeInterop); }

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

const BABEL_RUNTIME = "@babel/runtime-corejs2";

const presetEnvCompat = "#__secret_key__@babel/preset-env__compatibility";

const runtimeCompat = "#__secret_key__@babel/runtime__compatibility";

const has = Function.call.bind(Object.hasOwnProperty);

var _default = (0, _helperDefinePolyfillProvider.default)(function (api, {

  const resolve = api.createMetaResolver({

    global: _builtInDefinitions.BuiltIns,

    static: _builtInDefinitions.StaticProperties,

    instance: _builtInDefinitions.InstanceProperties

  const polyfills = (0, _addPlatformSpecificPolyfills.default)(api.targets, method, _corejs2BuiltIns.default);

  const coreJSBase = useBabelRuntime ? `${BABEL_RUNTIME}/core-js` : method === "usage-pure" ? "core-js/library/fn" : "core-js/modules";

      // Some polyfills aren't always available, for example

      // web.dom.iterable when targeting node

      if (has(polyfills, name) && shouldInjectPolyfill(name)) {

        utils.injectGlobalImport(`${coreJSBase}/${name}.js`);

    name.forEach(name => inject(name, utils));

  function maybeInjectPure(desc, hint, utils) {

    if (!pure || !shouldInjectPolyfill(name)) return;

    if (runtimeVersion && meta && meta.minRuntimeVersion && !(0, _helpers.hasMinVersion)(meta && meta.minRuntimeVersion, runtimeVersion)) {

    return utils.injectDefaultImport(`${coreJSBase}/${pure}${ext}`, hint);

    runtimeName: noRuntimeName ? null : BABEL_RUNTIME,

      if (meta.kind === "import" && meta.source === "core-js") {

        inject(Object.keys(polyfills), utils);

          utils.injectGlobalImport("regenerator-runtime/runtime.js");

      if (resolved.kind !== "global" && "object" in meta && meta.object && meta.placement === "prototype") {

        const low = meta.object.toLowerCase();

        deps = deps.filter(m => m.includes(low));

        if (meta.key === "Symbol.iterator") {

          path.replaceWith(t.callExpression(utils.injectDefaultImport(`${coreJSBase}/is-iterable${ext}`, "isIterable"), [path.node.right] // meta.kind === "in" narrows this

      if (path.parentPath.isUnaryExpression({

        // We can't compile destructuring.

        if (!path.isMemberExpression()) return;

        if (!path.isReferenced()) return;

        if (meta.key === "Symbol.iterator" && shouldInjectPolyfill("es6.symbol") && path.parentPath.isCallExpression({

        }) && path.parentPath.node.arguments.length === 0) {

          path.parentPath.replaceWith(t.callExpression(utils.injectDefaultImport(`${coreJSBase}/get-iterator${ext}`, "getIterator"), [path.node.object]));

      const id = maybeInjectPure(resolved.desc, resolved.name, utils);

    visitor: method === "usage-global" && {

          inject("web.dom.iterable", api.getUtils(path));

      "ForOfStatement|ArrayPattern"(path) {

        _builtInDefinitions.CommonIterators.forEach(name => inject(name, api.getUtils(path)));

  "name": "babel-plugin-polyfill-corejs2",

  "description": "A Babel plugin to inject imports to core-js@2 polyfills",

    "url": "https://github.com/babel/babel-polyfills.git",

    "directory": "packages/babel-plugin-polyfill-corejs2"

    "@babel/helper-define-polyfill-provider": "^0.4.0",

    "@babel/helper-plugin-test-runner": "^7.16.7",

    "@babel/plugin-transform-for-of": "^7.16.7",

    "@babel/plugin-transform-modules-commonjs": "^7.17.7"

  "gitHead": "391a1f4049fe1d6943ca8e91cf7e2e23f3f1ef73"

  "gitHead": "4b3c67a6a946df756123952a0033dc4426696131"

		@@ -34,6 +34,5 @@ "use strict";
		[presetEnvCompat]: {
		entryInjectRegenerator
		} = {
		entryInjectRegenerator: false
		},
		entryInjectRegenerator = false,
		noRuntimeName = false
		} = {},
		[runtimeCompat]: {
		@@ -90,3 +89,3 @@ useBabelRuntime = false,
		name: "corejs2",
		runtimeName: BABEL_RUNTIME,
		runtimeName: noRuntimeName ? null : BABEL_RUNTIME,
		polyfills,
		@@ -93,0 +92,0 @@

Improved metrics

Worsened metrics

		{
		"name": "babel-plugin-polyfill-corejs2",
		"version": "0.4.0",
		"version": "0.4.1",
		"description": "A Babel plugin to inject imports to core-js@2 polyfills",
		@@ -42,3 +42,3 @@ "repository": {
		},
		"gitHead": "391a1f4049fe1d6943ca8e91cf7e2e23f3f1ef73"
		"gitHead": "4b3c67a6a946df756123952a0033dc4426696131"
		}