This example demonstrates Scope Hoisting in combination with Code Splitting.
This is the dependency graph for the example: (solid lines express sync imports, dashed lines async imports)
All modules except cjs are EcmaScript modules. cjs is a CommonJs module.
The interesting thing here is that putting all modules in single scope won't work, because of multiple reasons:
- Modules
lazy,c,dandcjsneed to be in a separate chunk - Module
sharedis accessed by two chunks (different scopes) - Module
cjsis a CommonJs module
webpack therefore uses a approach called "Partial Scope Hoisting" or "Module concatenation", which chooses the largest possible subsets of ES modules which can be scope hoisted and combines them with the default webpack primitives.
While module concatentation identifiers in modules are renamed to avoid conflicts and internal imports are simplified. External imports and exports from the root module use the existing ESM constructs.
import { a, x, y } from "a";
import * as b from "b";
import("./lazy").then(function(lazy) {
console.log(a, b.a(), x, y, lazy.c, lazy.d.a, lazy.x, lazy.y);
});export * from "c";
import * as d from "d";
export { d };// module a
export var a = "a";
export * from "shared";// module b
export function a() {
return "b";
};// module c
import { c as e } from "cjs";
export var c = String.fromCharCode(e.charCodeAt(0) - 2);
export { x, y } from "shared";// module d
export var a = "d";// module cjs (commonjs)
exports.c = "e";// shared module
export var x = "x";
export * from "shared2";// shared2 module
export var y = "y";var webpack = require("../../");
module.exports = {
plugins: [
new webpack.optimize.ModuleConcatenationPlugin()
]
};/******/ (function(modules) { /* webpackBootstrap */ })
/******/ (function(modules) { // webpackBootstrap
/******/ // install a JSONP callback for chunk loading
/******/ var parentJsonpFunction = window["webpackJsonp"];
/******/ window["webpackJsonp"] = function webpackJsonpCallback(chunkIds, moreModules, executeModules) {
/******/ // add "moreModules" to the modules object,
/******/ // then flag all "chunkIds" as loaded and fire callback
/******/ var moduleId, chunkId, i = 0, resolves = [], result;
/******/ for(;i < chunkIds.length; i++) {
/******/ chunkId = chunkIds[i];
/******/ if(installedChunks[chunkId]) {
/******/ resolves.push(installedChunks[chunkId][0]);
/******/ }
/******/ installedChunks[chunkId] = 0;
/******/ }
/******/ for(moduleId in moreModules) {
/******/ if(Object.prototype.hasOwnProperty.call(moreModules, moduleId)) {
/******/ modules[moduleId] = moreModules[moduleId];
/******/ }
/******/ }
/******/ if(parentJsonpFunction) parentJsonpFunction(chunkIds, moreModules, executeModules);
/******/ while(resolves.length) {
/******/ resolves.shift()();
/******/ }
/******/
/******/ };
/******/
/******/ // The module cache
/******/ var installedModules = {};
/******/
/******/ // objects to store loaded and loading chunks
/******/ var installedChunks = {
/******/ 1: 0
/******/ };
/******/
/******/ // The require function
/******/ function __webpack_require__(moduleId) {
/******/
/******/ // Check if module is in cache
/******/ if(installedModules[moduleId]) {
/******/ return installedModules[moduleId].exports;
/******/ }
/******/ // Create a new module (and put it into the cache)
/******/ var module = installedModules[moduleId] = {
/******/ i: moduleId,
/******/ l: false,
/******/ exports: {}
/******/ };
/******/
/******/ // Execute the module function
/******/ modules[moduleId].call(module.exports, module, module.exports, __webpack_require__);
/******/
/******/ // Flag the module as loaded
/******/ module.l = true;
/******/
/******/ // Return the exports of the module
/******/ return module.exports;
/******/ }
/******/
/******/ // This file contains only the entry chunk.
/******/ // The chunk loading function for additional chunks
/******/ __webpack_require__.e = function requireEnsure(chunkId) {
/******/ var installedChunkData = installedChunks[chunkId];
/******/ if(installedChunkData === 0) {
/******/ return new Promise(function(resolve) { resolve(); });
/******/ }
/******/
/******/ // a Promise means "currently loading".
/******/ if(installedChunkData) {
/******/ return installedChunkData[2];
/******/ }
/******/
/******/ // setup Promise in chunk cache
/******/ var promise = new Promise(function(resolve, reject) {
/******/ installedChunkData = installedChunks[chunkId] = [resolve, reject];
/******/ });
/******/ installedChunkData[2] = promise;
/******/
/******/ // start chunk loading
/******/ var head = document.getElementsByTagName('head')[0];
/******/ var script = document.createElement('script');
/******/ script.type = 'text/javascript';
/******/ script.charset = 'utf-8';
/******/ script.async = true;
/******/ script.timeout = 120000;
/******/
/******/ if (__webpack_require__.nc) {
/******/ script.setAttribute("nonce", __webpack_require__.nc);
/******/ }
/******/ script.src = __webpack_require__.p + "" + chunkId + ".output.js";
/******/ var timeout = setTimeout(onScriptComplete, 120000);
/******/ script.onerror = script.onload = onScriptComplete;
/******/ function onScriptComplete() {
/******/ // avoid mem leaks in IE.
/******/ script.onerror = script.onload = null;
/******/ clearTimeout(timeout);
/******/ var chunk = installedChunks[chunkId];
/******/ if(chunk !== 0) {
/******/ if(chunk) {
/******/ chunk[1](new Error('Loading chunk ' + chunkId + ' failed.'));
/******/ }
/******/ installedChunks[chunkId] = undefined;
/******/ }
/******/ };
/******/ head.appendChild(script);
/******/
/******/ return promise;
/******/ };
/******/
/******/ // expose the modules object (__webpack_modules__)
/******/ __webpack_require__.m = modules;
/******/
/******/ // expose the module cache
/******/ __webpack_require__.c = installedModules;
/******/
/******/ // define getter function for harmony exports
/******/ __webpack_require__.d = function(exports, name, getter) {
/******/ if(!__webpack_require__.o(exports, name)) {
/******/ Object.defineProperty(exports, name, {
/******/ configurable: false,
/******/ enumerable: true,
/******/ get: getter
/******/ });
/******/ }
/******/ };
/******/
/******/ // getDefaultExport function for compatibility with non-harmony modules
/******/ __webpack_require__.n = function(module) {
/******/ var getter = module && module.__esModule ?
/******/ function getDefault() { return module['default']; } :
/******/ function getModuleExports() { return module; };
/******/ __webpack_require__.d(getter, 'a', getter);
/******/ return getter;
/******/ };
/******/
/******/ // Object.prototype.hasOwnProperty.call
/******/ __webpack_require__.o = function(object, property) { return Object.prototype.hasOwnProperty.call(object, property); };
/******/
/******/ // __webpack_public_path__
/******/ __webpack_require__.p = "js/";
/******/
/******/ // on error function for async loading
/******/ __webpack_require__.oe = function(err) { console.error(err); throw err; };
/******/
/******/ // Load entry module and return exports
/******/ return __webpack_require__(__webpack_require__.s = 1);
/******/ })
/************************************************************************//******/ ([
/* 0 */
/*!********************************************!*\
!*** ./node_modules/shared.js + 1 modules ***!
\********************************************/
/*! exports provided: x, y */
/*! exports used: x, y */
/***/ (function(module, __webpack_exports__, __webpack_require__) {
"use strict";
Object.defineProperty(__webpack_exports__, "__esModule", { value: true });
// CONCATENATED MODULE: ./node_modules/shared2.js
// shared2 module
var y = "y";
// CONCATENATED MODULE: ./node_modules/shared.js
/* harmony export (binding) */ __webpack_require__.d(__webpack_exports__, "a", function() { return x; });
/* concated harmony reexport */__webpack_require__.d(__webpack_exports__, "b", function() { return y; });
// shared module
var x = "x";
/***/ }),
/* 1 */
/*!********************************!*\
!*** ./example.js + 2 modules ***!
\********************************/
/*! no static exports found */
/*! all exports used */
/*! ModuleConcatenation (inner): module is an entrypoint */
/***/ (function(module, __webpack_exports__, __webpack_require__) {
"use strict";
Object.defineProperty(__webpack_exports__, "__esModule", { value: true });
// CONCATENATED MODULE: ./node_modules/a.js
/* harmony import */ var __WEBPACK_IMPORTED_MODULE_0_shared__ = __webpack_require__(/*! shared */ 0);
// module a
var a = "a";
// CONCATENATED MODULE: ./node_modules/b.js
// module b
function b_a() {
return "b";
};
// CONCATENATED MODULE: ./example.js
__webpack_require__.e/* import() */(0).then(__webpack_require__.bind(null, /*! ./lazy */ 3)).then(function(lazy) {
console.log(a, b_a(), __WEBPACK_IMPORTED_MODULE_0_shared__["a"], __WEBPACK_IMPORTED_MODULE_0_shared__["b"], lazy.c, lazy.d.a, lazy.x, lazy.y);
});
/***/ })
/******/ ]);webpackJsonp([0],[
/* 0 */,
/* 1 */,
/* 2 */
/*!*****************************!*\
!*** ./node_modules/cjs.js ***!
\*****************************/
/*! no static exports found */
/*! exports used: c */
/***/ (function(module, exports) {
// module cjs (commonjs)
exports.c = "e";
/***/ }),
/* 3 */
/*!*****************************!*\
!*** ./lazy.js + 2 modules ***!
\*****************************/
/*! exports provided: d, c, x, y */
/*! all exports used */
/*! ModuleConcatenation (inner): module is used with non-harmony imports from ./example.js */
/***/ (function(module, __webpack_exports__, __webpack_require__) {
"use strict";
Object.defineProperty(__webpack_exports__, "__esModule", { value: true });
// CONCATENATED MODULE: ./node_modules/c.js
/* harmony import */ var __WEBPACK_IMPORTED_MODULE_0_cjs__ = __webpack_require__(/*! cjs */ 2);
/* harmony import */ var __WEBPACK_IMPORTED_MODULE_0_cjs___default = __webpack_require__.n(__WEBPACK_IMPORTED_MODULE_0_cjs__);
/* harmony import */ var __WEBPACK_IMPORTED_MODULE_1_shared__ = __webpack_require__(/*! shared */ 0);
// module c
var c = String.fromCharCode(__WEBPACK_IMPORTED_MODULE_0_cjs__["c"].charCodeAt(0) - 2);
// CONCATENATED MODULE: ./node_modules/d.js
var d_namespaceObject = {};
__webpack_require__.d(d_namespaceObject, "a", function() { return a; });
// module d
var a = "d";
// CONCATENATED MODULE: ./lazy.js
/* concated harmony reexport */__webpack_require__.d(__webpack_exports__, "c", function() { return c; });
/* concated harmony reexport */__webpack_require__.d(__webpack_exports__, "x", function() { return __WEBPACK_IMPORTED_MODULE_1_shared__["a"]; });
/* concated harmony reexport */__webpack_require__.d(__webpack_exports__, "y", function() { return __WEBPACK_IMPORTED_MODULE_1_shared__["b"]; });
/* concated harmony reexport */__webpack_require__.d(__webpack_exports__, "d", function() { return d_namespaceObject; });
/***/ })
]);Minimized
webpackJsonp([0],[,,function(n,r){r.c="e"},function(n,r,t){"use strict";Object.defineProperty(r,"__esModule",{value:!0});var e=t(2),u=(t.n(e),t(0)),c=String.fromCharCode(e.c.charCodeAt(0)-2),o={};t.d(o,"a",function(){return d});var d="d";t.d(r,"c",function(){return c}),t.d(r,"x",function(){return u.a}),t.d(r,"y",function(){return u.b}),t.d(r,"d",function(){return o})}]);Hash: 26f89d6006fb6c5a1fa1
Version: webpack 3.0.0-rc.0
Asset Size Chunks Chunk Names
0.output.js 1.95 kB 0 [emitted]
output.js 7.45 kB 1 [emitted] main
Entrypoint main = output.js
chunk {0} 0.output.js 276 bytes {1} [rendered]
> [] 4:0-16
[2] ./node_modules/cjs.js 44 bytes {0} [built]
[only some exports used: c]
harmony import cjs [3] ./lazy.js + 2 modules 2:0-29
[3] ./lazy.js + 2 modules 232 bytes {0} [built]
[exports: d, c, x, y]
import() ./lazy [] ./example.js 4:0-16
chunk {1} output.js (main) 385 bytes [entry] [rendered]
> main []
[0] ./node_modules/shared.js + 1 modules 105 bytes {1} [built]
[exports: x, y]
[only some exports used: x, y]
harmony import shared [1] ./example.js + 2 modules 3:0-23
harmony import shared [3] ./lazy.js + 2 modules 6:0-30
[1] ./example.js + 2 modules 280 bytes {1} [built]
[0] ./node_modules/shared.js + 1 modules 105 bytes {1} [built]
[exports: x, y]
[only some exports used: x, y]
harmony import shared [1] ./example.js + 2 modules 3:0-23
harmony import shared [3] ./lazy.js + 2 modules 6:0-30
[1] ./example.js + 2 modules 280 bytes {1} [built]
[2] ./node_modules/cjs.js 44 bytes {0} [built]
[only some exports used: c]
harmony import cjs [3] ./lazy.js + 2 modules 2:0-29
[3] ./lazy.js + 2 modules 232 bytes {0} [built]
[exports: d, c, x, y]
import() ./lazy [] ./example.js 4:0-16
Hash: 26f89d6006fb6c5a1fa1
Version: webpack 3.0.0-rc.0
Asset Size Chunks Chunk Names
0.output.js 373 bytes 0 [emitted]
output.js 1.66 kB 1 [emitted] main
Entrypoint main = output.js
chunk {0} 0.output.js 276 bytes {1} [rendered]
> [] 4:0-16
[2] ./node_modules/cjs.js 44 bytes {0} [built]
[only some exports used: c]
harmony import cjs [3] ./lazy.js + 2 modules 2:0-29
[3] ./lazy.js + 2 modules 232 bytes {0} [built]
[exports: d, c, x, y]
import() ./lazy [] ./example.js 4:0-16
chunk {1} output.js (main) 385 bytes [entry] [rendered]
> main []
[0] ./node_modules/shared.js + 1 modules 105 bytes {1} [built]
[exports: x, y]
[only some exports used: x, y]
harmony import shared [1] ./example.js + 2 modules 3:0-23
harmony import shared [3] ./lazy.js + 2 modules 6:0-30
[1] ./example.js + 2 modules 280 bytes {1} [built]
[0] ./node_modules/shared.js + 1 modules 105 bytes {1} [built]
[exports: x, y]
[only some exports used: x, y]
harmony import shared [1] ./example.js + 2 modules 3:0-23
harmony import shared [3] ./lazy.js + 2 modules 6:0-30
[1] ./example.js + 2 modules 280 bytes {1} [built]
[2] ./node_modules/cjs.js 44 bytes {0} [built]
[only some exports used: c]
harmony import cjs [3] ./lazy.js + 2 modules 2:0-29
[3] ./lazy.js + 2 modules 232 bytes {0} [built]
[exports: d, c, x, y]
import() ./lazy [] ./example.js 4:0-16