This example show how to use Code Splitting with the ES6 module syntax.
The standard import is sync.
import(module: string) -> Promise can be used to load modules on demand. This acts as split point for webpack and creates a chunk.
Providing dynamic expressions to import is possible. The same limits as with dynamic expressions in require calls apply here. Each possible module creates an additional chunk. In this example import("c/" + name) creates two additional chunks (one for each file in node_modules/c/). This is called "async context".
import a from "a";
import("b").then(function(b) {
console.log("b loaded", b);
})
function loadC(name) {
return import("c/" + name);
}
Promise.all([loadC("1"), loadC("2")]).then(function(arr) {
console.log("c/1 and c/2 loaded", arr);
});/******/ (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 = {
/******/ 3: 0
/******/ };
/******/
/******/ var resolvedPromise = new Promise(function(resolve) { resolve(); });
/******/
/******/ // 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) {
/******/ if(installedChunks[chunkId] === 0) {
/******/ return resolvedPromise;
/******/ }
/******/
/******/ // a Promise means "currently loading".
/******/ if(installedChunks[chunkId]) {
/******/ return installedChunks[chunkId][2];
/******/ }
/******/
/******/ // setup Promise in chunk cache
/******/ var promise = new Promise(function(resolve, reject) {
/******/ installedChunks[chunkId] = [resolve, reject];
/******/ });
/******/ installedChunks[chunkId][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;
/******/
/******/ // identity function for calling harmony imports with the correct context
/******/ __webpack_require__.i = function(value) { return value; };
/******/
/******/ // 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 = 4);
/******/ })
/************************************************************************//******/ ([
/* 0 */
/* unknown exports provided */
/*!****************!*\
!*** ./~/a.js ***!
\****************/
/***/ (function(module, exports) {
// module a
/***/ }),
/* 1 */
/* unknown exports provided */
/* all exports used */
/*!***************************!*\
!*** ./~/c lazy ^\.\/.*$ ***!
\***************************/
/***/ (function(module, exports, __webpack_require__) {
var map = {
"./1": [
2,
1
],
"./1.js": [
2,
1
],
"./2": [
3,
0
],
"./2.js": [
3,
0
]
};
function webpackAsyncContext(req) {
var ids = map[req];
if(!ids)
return Promise.reject(new Error("Cannot find module '" + req + "'."));
return __webpack_require__.e(ids[1]).then(function() {
return __webpack_require__(ids[0]);
});
};
webpackAsyncContext.keys = function webpackAsyncContextKeys() {
return Object.keys(map);
};
module.exports = webpackAsyncContext;
webpackAsyncContext.id = 1;
/***/ }),
/* 2 */,
/* 3 */,
/* 4 */
/* unknown exports provided */
/* all exports used */
/*!********************!*\
!*** ./example.js ***!
\********************/
/***/ (function(module, __webpack_exports__, __webpack_require__) {
"use strict";
Object.defineProperty(__webpack_exports__, "__esModule", { value: true });
/* harmony import */ var __WEBPACK_IMPORTED_MODULE_0_a__ = __webpack_require__(/*! a */ 0);
/* harmony import */ var __WEBPACK_IMPORTED_MODULE_0_a___default = __webpack_require__.n(__WEBPACK_IMPORTED_MODULE_0_a__);
__webpack_require__.e/* import() */(2).then(__webpack_require__.bind(null, /*! b */ 5)).then(function(b) {
console.log("b loaded", b);
})
function loadC(name) {
return __webpack_require__(/*! c */ 1)("./" + name);
}
Promise.all([loadC("1"), loadC("2")]).then(function(arr) {
console.log("c/1 and c/2 loaded", arr);
});
/***/ })
/******/ ]);Hash: d615402477252ba51b19
Version: webpack 2.6.0
Asset Size Chunks Chunk Names
0.output.js 218 bytes 0 [emitted]
1.output.js 218 bytes 1 [emitted]
2.output.js 210 bytes 2 [emitted]
output.js 7.65 kB 3 [emitted] main
Entrypoint main = output.js
chunk {0} 0.output.js 13 bytes {3} [rendered]
[3] ./~/c/2.js 13 bytes {0} [optional] [built]
context element ./2 [1] ./~/c lazy ^\.\/.*$ ./2
context element ./2.js [1] ./~/c lazy ^\.\/.*$ ./2.js
chunk {1} 1.output.js 13 bytes {3} [rendered]
[2] ./~/c/1.js 13 bytes {1} [optional] [built]
context element ./1 [1] ./~/c lazy ^\.\/.*$ ./1
context element ./1.js [1] ./~/c lazy ^\.\/.*$ ./1.js
chunk {2} 2.output.js 11 bytes {3} [rendered]
> [4] ./example.js 3:0-11
[5] ./~/b.js 11 bytes {2} [built]
import() b [4] ./example.js 3:0-11
chunk {3} output.js (main) 427 bytes [entry] [rendered]
> main [4] ./example.js
[0] ./~/a.js 11 bytes {3} [built]
[no exports used]
harmony import a [4] ./example.js 1:0-18
[1] ./~/c lazy ^\.\/.*$ 160 bytes {3} [built]
import() context lazy c [4] ./example.js 8:8-27
[4] ./example.js 256 bytes {3} [built]
Hash: d615402477252ba51b19
Version: webpack 2.6.0
Asset Size Chunks Chunk Names
0.output.js 38 bytes 0 [emitted]
1.output.js 38 bytes 1 [emitted]
2.output.js 38 bytes 2 [emitted]
output.js 1.93 kB 3 [emitted] main
Entrypoint main = output.js
chunk {0} 0.output.js 13 bytes {3} [rendered]
[3] ./~/c/2.js 13 bytes {0} [optional] [built]
context element ./2 [1] ./~/c lazy ^\.\/.*$ ./2
context element ./2.js [1] ./~/c lazy ^\.\/.*$ ./2.js
chunk {1} 1.output.js 13 bytes {3} [rendered]
[2] ./~/c/1.js 13 bytes {1} [optional] [built]
context element ./1 [1] ./~/c lazy ^\.\/.*$ ./1
context element ./1.js [1] ./~/c lazy ^\.\/.*$ ./1.js
chunk {2} 2.output.js 11 bytes {3} [rendered]
> [4] ./example.js 3:0-11
[5] ./~/b.js 11 bytes {2} [built]
import() b [4] ./example.js 3:0-11
chunk {3} output.js (main) 427 bytes [entry] [rendered]
> main [4] ./example.js
[0] ./~/a.js 11 bytes {3} [built]
[no exports used]
harmony import a [4] ./example.js 1:0-18
[1] ./~/c lazy ^\.\/.*$ 160 bytes {3} [built]
import() context lazy c [4] ./example.js 8:8-27
[4] ./example.js 256 bytes {3} [built]