12 KiB
12 KiB
This example illustrates a very simple case of Code Splitting with require.ensure
.
a
andb
are required normally via CommonJSc
is depended through therequire.ensure
array.- This means: make it available, but don't execute it
- webpack will load it on demand
b
andd
are required via CommonJs in therequire.ensure
callback- webpack detects that these are in the on-demand-callback and
- will load them on demand
- webpacks optimizer can optimize
b
away- as it is already available through the parent chunks
You can see that webpack outputs two files/chunks:
output.js
is the entry chunk and contains- the module system
- chunk loading logic
- the entry point
example.js
- module
a
- module
b
1.output.js
is an additional chunk (on demand loaded) and contains- module
c
- module
d
- module
You can see that chunks are loaded via JSONP. The additional chunks are pretty small and minimize well.
example.js
var a = require("a");
var b = require("b");
require.ensure(["c"], function(require) {
require("b").xyz();
var d = require("d");
});
dist/output.js
/******/ (() => { // webpackBootstrap
/******/ var __webpack_modules__ = ([
/* 0 */,
/* 1 */
/*!***************************!*\
!*** ./node_modules/a.js ***!
\***************************/
/*! exports [maybe provided (runtime-defined)] [no usage info] */
/*! runtime requirements: */
/***/ (() => {
// module a
/***/ }),
/* 2 */
/*!***************************!*\
!*** ./node_modules/b.js ***!
\***************************/
/*! exports [maybe provided (runtime-defined)] [no usage info] */
/*! runtime requirements: */
/***/ (() => {
// module b
/***/ })
/******/ ]);
/* webpack runtime code */
/************************************************************************/
/******/ // The module cache
/******/ var __webpack_module_cache__ = {};
/******/
/******/ // The require function
/******/ function __webpack_require__(moduleId) {
/******/ // Check if module is in cache
/******/ if(__webpack_module_cache__[moduleId]) {
/******/ return __webpack_module_cache__[moduleId].exports;
/******/ }
/******/ // Create a new module (and put it into the cache)
/******/ var module = __webpack_module_cache__[moduleId] = {
/******/ i: moduleId,
/******/ l: false,
/******/ exports: {}
/******/ };
/******/
/******/ // Execute the module function
/******/ __webpack_modules__[moduleId](module, module.exports, __webpack_require__);
/******/
/******/ // Flag the module as loaded
/******/ module.l = true;
/******/
/******/ // Return the exports of the module
/******/ return module.exports;
/******/ }
/******/
/******/ // expose the modules object (__webpack_modules__)
/******/ __webpack_require__.m = __webpack_modules__;
/******/
/************************************************************************/
/******/ /* webpack/runtime/ensure chunk */
/******/ !function() {
/******/ __webpack_require__.f = {};
/******/ // This file contains only the entry chunk.
/******/ // The chunk loading function for additional chunks
/******/ __webpack_require__.e = (chunkId) => {
/******/ return Promise.all(Object.keys(__webpack_require__.f).reduce((promises, key) => {
/******/ __webpack_require__.f[key](chunkId, promises);
/******/ return promises;
/******/ }, []));
/******/ };
/******/ }();
/******/
/******/ /* webpack/runtime/get javascript chunk filename */
/******/ !function() {
/******/ // This function allow to reference async chunks
/******/ __webpack_require__.u = (chunkId) => {
/******/ // return url for filenames based on template
/******/ return "" + chunkId + ".output.js";
/******/ };
/******/ }();
/******/
/******/ /* webpack/runtime/publicPath */
/******/ !function() {
/******/ __webpack_require__.p = "dist/";
/******/ }();
/******/
/******/ /* webpack/runtime/jsonp chunk loading */
/******/ !function() {
/******/
/******/
/******/ // object to store loaded and loading chunks
/******/ // undefined = chunk not loaded, null = chunk preloaded/prefetched
/******/ // Promise = chunk loading, 0 = chunk loaded
/******/ var installedChunks = {
/******/ 179: 0
/******/ };
/******/
/******/
/******/
/******/
/******/ __webpack_require__.f.j = (chunkId, promises) => {
/******/ // JSONP chunk loading for javascript
/******/ var installedChunkData = Object.prototype.hasOwnProperty.call(installedChunks, chunkId) ? installedChunks[chunkId] : undefined;
/******/ if(installedChunkData !== 0) { // 0 means "already installed".
/******/
/******/ // a Promise means "currently loading".
/******/ if(installedChunkData) {
/******/ promises.push(installedChunkData[2]);
/******/ } else {
/******/ if(true) { // all chunks have JS
/******/ // setup Promise in chunk cache
/******/ var promise = new Promise((resolve, reject) => {
/******/ installedChunkData = installedChunks[chunkId] = [resolve, reject];
/******/ });
/******/ promises.push(installedChunkData[2] = promise);
/******/
/******/ // start chunk loading
/******/ var url = __webpack_require__.p + __webpack_require__.u(chunkId);
/******/ var loadingEnded = () => {
/******/ if(Object.prototype.hasOwnProperty.call(installedChunks, chunkId)) {
/******/ installedChunkData = installedChunks[chunkId];
/******/ if(installedChunkData !== 0) installedChunks[chunkId] = undefined;
/******/ if(installedChunkData) return installedChunkData[1];
/******/ }
/******/ };
/******/ var script = document.createElement('script');
/******/ var onScriptComplete;
/******/
/******/ script.charset = 'utf-8';
/******/ script.timeout = 120;
/******/ if (__webpack_require__.nc) {
/******/ script.setAttribute("nonce", __webpack_require__.nc);
/******/ }
/******/ script.src = url;
/******/
/******/ // create error before stack unwound to get useful stacktrace later
/******/ var error = new Error();
/******/ onScriptComplete = function (event) {
/******/ onScriptComplete = function() {};
/******/ // avoid mem leaks in IE.
/******/ script.onerror = script.onload = null;
/******/ clearTimeout(timeout);
/******/ var reportError = loadingEnded();
/******/ if(reportError) {
/******/ var errorType = event && (event.type === 'load' ? 'missing' : event.type);
/******/ var realSrc = event && event.target && event.target.src;
/******/ error.message = 'Loading chunk ' + chunkId + ' failed.\n(' + errorType + ': ' + realSrc + ')';
/******/ error.name = 'ChunkLoadError';
/******/ error.type = errorType;
/******/ error.request = realSrc;
/******/ reportError(error);
/******/ }
/******/ };
/******/ var timeout = setTimeout(function(){
/******/ onScriptComplete({ type: 'timeout', target: script });
/******/ }, 120000);
/******/ script.onerror = script.onload = onScriptComplete;
/******/ document.head.appendChild(script);
/******/ } else installedChunks[chunkId] = 0;
/******/
/******/ // no HMR
/******/ }
/******/ }
/******/
/******/ // no chunk preloading needed
/******/ };
/******/
/******/ // no prefetching
/******/
/******/ // no HMR
/******/
/******/ // no HMR manifest
/******/
/******/ // no deferred startup or startup prefetching
/******/
/******/ // install a JSONP callback for chunk loading
/******/ function webpackJsonpCallback(data) {
/******/ var chunkIds = data[0];
/******/ var moreModules = data[1];
/******/
/******/ var runtime = data[3];
/******/
/******/ // add "moreModules" to the modules object,
/******/ // then flag all "chunkIds" as loaded and fire callback
/******/ var moduleId, chunkId, i = 0, resolves = [];
/******/ for(;i < chunkIds.length; i++) {
/******/ chunkId = chunkIds[i];
/******/ if(Object.prototype.hasOwnProperty.call(installedChunks, chunkId) && installedChunks[chunkId]) {
/******/ resolves.push(installedChunks[chunkId][0]);
/******/ }
/******/ installedChunks[chunkId] = 0;
/******/ }
/******/ for(moduleId in moreModules) {
/******/ if(Object.prototype.hasOwnProperty.call(moreModules, moduleId)) {
/******/ __webpack_require__.m[moduleId] = moreModules[moduleId];
/******/ }
/******/ }
/******/ if(runtime) runtime(__webpack_require__);
/******/ if(parentJsonpFunction) parentJsonpFunction(data);
/******/
/******/ while(resolves.length) {
/******/ resolves.shift()();
/******/ }
/******/
/******/ };
/******/
/******/ var jsonpArray = window["webpackJsonp"] = window["webpackJsonp"] || [];
/******/ var oldJsonpFunction = jsonpArray.push.bind(jsonpArray);
/******/ jsonpArray.push = webpackJsonpCallback;
/******/
/******/ var parentJsonpFunction = oldJsonpFunction;
/******/ }();
/******/
/************************************************************************/
!function() {
/*!********************!*\
!*** ./example.js ***!
\********************/
/*! exports [maybe provided (runtime-defined)] [no usage info] */
/*! runtime requirements: __webpack_require__, __webpack_require__.e, __webpack_require__.* */
var a = __webpack_require__(/*! a */ 1);
var b = __webpack_require__(/*! b */ 2);
__webpack_require__.e(/*! require.ensure */ 796).then((function(require) {
__webpack_require__(/*! b */ 2).xyz();
var d = __webpack_require__(/*! d */ 4);
}).bind(null, __webpack_require__)).catch(__webpack_require__.oe);
}();
/******/ })()
;
dist/796.output.js
(window["webpackJsonp"] = window["webpackJsonp"] || []).push([[796],[
/* 0 */,
/* 1 */,
/* 2 */,
/* 3 */
/*!***************************!*\
!*** ./node_modules/c.js ***!
\***************************/
/*! exports [maybe provided (runtime-defined)] [no usage info] */
/*! runtime requirements: */
/***/ (() => {
// module c
/***/ }),
/* 4 */
/*!***************************!*\
!*** ./node_modules/d.js ***!
\***************************/
/*! exports [maybe provided (runtime-defined)] [no usage info] */
/*! runtime requirements: */
/***/ (() => {
// module d
/***/ })
]]);
Minimized
(window.webpackJsonp=window.webpackJsonp||[]).push([[796],{286:()=>{},882:()=>{}}]);
Info
Unoptimized
Hash: 0a1b2c3d4e5f6a7b8c9d
Version: webpack 5.0.0-beta.6
Asset Size
796.output.js 582 bytes [emitted]
output.js 8.45 KiB [emitted] [name: main]
Entrypoint main = output.js
chunk output.js (main) 161 bytes (javascript) 4.23 KiB (runtime) [entry] [rendered]
> ./example.js main
./example.js 139 bytes [built]
[used exports unknown]
entry ./example.js main
./node_modules/a.js 11 bytes [built]
[used exports unknown]
cjs require a ./example.js 1:8-20
./node_modules/b.js 11 bytes [built]
[used exports unknown]
cjs require b ./example.js 2:8-20
cjs require b ./example.js 4:4-16
+ 4 hidden chunk modules
chunk 796.output.js 22 bytes [rendered]
> ./example.js 3:0-6:2
./node_modules/c.js 11 bytes [built]
[used exports unknown]
require.ensure item c ./example.js 3:0-6:2
./node_modules/d.js 11 bytes [built]
[used exports unknown]
cjs require d ./example.js 5:12-24
Production mode
Hash: 0a1b2c3d4e5f6a7b8c9d
Version: webpack 5.0.0-beta.6
Asset Size
796.output.js 84 bytes [emitted]
output.js 1.5 KiB [emitted] [name: main]
Entrypoint main = output.js
chunk output.js (main) 161 bytes (javascript) 4.23 KiB (runtime) [entry] [rendered]
> ./example.js main
./example.js 139 bytes [built]
[no exports used]
entry ./example.js main
./node_modules/a.js 11 bytes [built]
cjs require a ./example.js 1:8-20
./node_modules/b.js 11 bytes [built]
cjs require b ./example.js 2:8-20
cjs require b ./example.js 4:4-16
+ 4 hidden chunk modules
chunk 796.output.js 22 bytes [rendered]
> ./example.js 3:0-6:2
./node_modules/c.js 11 bytes [built]
require.ensure item c ./example.js 3:0-6:2
./node_modules/d.js 11 bytes [built]
cjs require d ./example.js 5:12-24