原文链接：
译者：这个示例演示了与代码拆分相结合的 Scope Hoisting。
这是示例的依赖图：（实线表示同步导入，虚线表示异步导入）
除 cjs 之外的所有模块都是 EcmaScript 模块。cjs 是 CommonJs 模块。
有趣的是，将所有模块放在单一范围（scope）内将无法正常工作，原因如下：
- 模块
lazy,c,d和cjs需要在一个单独的块（chunk） - 模块
shared可以被两个 chunk 访问（不同的范围） - 模块
cjs是一个 CommonJs 模块
因此，Webpack 使用一种称为“局部范围提升（Partial Scope Hoisting）”或“模块级联”的方法，该方法选择可以可以覆盖 Scope Hoisting 范围的 ES 模块的最大子集，并将其与默认的 webpack 原语(primitives)相结合。
为了避免冲突，模块中的模块连接标识符被重命名，并简化了内部导入。根模块的外部导入和导出使用现有的 ESM 结构。
example.js
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);}); lazy.js
export * from "c";import * as d from "d";export { d }; a.js
// module aexport var a = "a";export * from "shared";
b.js
// module bexport function a() { return "b";}; c.js
// module cimport { c as e } from "cjs";export var c = String.fromCharCode(e.charCodeAt(0) - 2);export { x, y } from "shared"; d.js
// module dexport var a = "d";
cjs.js
// module cjs (commonjs)exports.c = "e";
shared.js
// shared moduleexport var x = "x";export * from "shared2";
shared2.js
// shared2 moduleexport var y = "y";
webpack.config.js
var webpack = require("../../");module.exports = { plugins: [ new webpack.optimize.ModuleConcatenationPlugin() ]}; js/output.js
/******/ (function(modules) { /* webpackBootstrap */ })...... /******/ ([/* 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 modulevar 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 modulevar x = "x";/***/ }),/* 1 *//*!********************************!*\ !*** ./example.js + 2 modules ***! \********************************//*! exports provided: *//*! all exports used *//*! ModuleConcatenation bailout: Module is an entry point *//***/ (function(module, __webpack_exports__, __webpack_require__) {"use strict";Object.defineProperty(__webpack_exports__, "__esModule", { value: true });// EXTERNAL MODULE: ./node_modules/shared.js + 1 modulesvar shared = __webpack_require__(0);// CONCATENATED MODULE: ./node_modules/a.js// module avar a = "a";// CONCATENATED MODULE: ./node_modules/b.js// module bfunction 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(), shared["a" /* x */], shared["b" /* y */], lazy.c, lazy.d.a, lazy.x, lazy.y);});/***/ })/******/ ]); js/0.output.js
webpackJsonp([0],[/* 0 */,/* 1 */,/* 2 *//*!*****************************!*\ !*** ./node_modules/cjs.js ***! \*****************************//*! no static exports found *//*! exports used: c *//*! ModuleConcatenation bailout: Module is not an ECMAScript module *//***/ (function(module, exports) {// module cjs (commonjs)exports.c = "e";/***/ }),/* 3 *//*!*****************************!*\ !*** ./lazy.js + 2 modules ***! \*****************************//*! exports provided: d, c, x, y *//*! all exports used *//*! ModuleConcatenation bailout: Module is referenced from these modules with unsupported syntax: ./example.js (referenced with import()) *//***/ (function(module, __webpack_exports__, __webpack_require__) {"use strict";Object.defineProperty(__webpack_exports__, "__esModule", { value: true });var d_namespaceObject = {};__webpack_require__.d(d_namespaceObject, "a", function() { return a; });// EXTERNAL MODULE: ./node_modules/cjs.jsvar cjs = __webpack_require__(2);var cjs_default = /*#__PURE__*/__webpack_require__.n(cjs);// EXTERNAL MODULE: ./node_modules/shared.js + 1 modulesvar shared = __webpack_require__(0);// CONCATENATED MODULE: ./node_modules/c.js// module cvar c = String.fromCharCode(cjs["c"].charCodeAt(0) - 2);// CONCATENATED MODULE: ./node_modules/d.js// module dvar 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 shared["a" /* x */]; });/* concated harmony reexport */__webpack_require__.d(__webpack_exports__, "y", function() { return shared["b" /* y */]; });/* 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.d(e,"a",function(){return d});var u=t(2),c=t(0),o=String.fromCharCode(u.c.charCodeAt(0)-2),d="d";t.d(r,"c",function(){return o}),t.d(r,"x",function(){return c.a}),t.d(r,"y",function(){return c.b}),t.d(r,"d",function(){return e})}]); Info
Uncompressed
Hash: 6596ce0a50ccbbaa89c6Version: webpack 3.5.1 Asset Size Chunks Chunk Names0.output.js 1.9 kB 0 [emitted] output.js 7.39 kB 1 [emitted] mainEntrypoint main = output.jschunk {0} 0.output.js 286 bytes {1} [rendered] > [] 4:0-16 [3] ./lazy.js + 2 modules 242 bytes {0} [built] [exports: d, c, x, y] import() ./lazy [] ./example.js 4:0-16 + 1 hidden modulechunk {1} output.js (main) 390 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 285 bytes {1} [built] [no exports] Minimized (uglify-js, no zip)
Hash: 6596ce0a50ccbbaa89c6Version: webpack 3.5.1 Asset Size Chunks Chunk Names0.output.js 364 bytes 0 [emitted] output.js 1.66 kB 1 [emitted] mainEntrypoint main = output.jschunk {0} 0.output.js 286 bytes {1} [rendered] > [] 4:0-16 [3] ./lazy.js + 2 modules 242 bytes {0} [built] [exports: d, c, x, y] import() ./lazy [] ./example.js 4:0-16 + 1 hidden modulechunk {1} output.js (main) 390 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 285 bytes {1} [built] [no exports] 欢迎关注我的公众号，关注前端文章：
