webpack/lib/runtime/OnChunksLoadedRuntimeModule.js

Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support loaders to preprocess files, i.e. json, jsx, es7, css, less, ... and your custom stuff.

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
*/

"use strict";

const RuntimeGlobals = require("../RuntimeGlobals");
const RuntimeModule = require("../RuntimeModule");
const Template = require("../Template");

class OnChunksLoadedRuntimeModule extends RuntimeModule {
	constructor() {
		super("chunk loaded");
	}

	/**
	 * @returns {string} runtime code
	 */
	generate() {
		const { compilation } = this;
		const { runtimeTemplate } = compilation;
		return Template.asString([
			"var deferred = [];",
			`${RuntimeGlobals.onChunksLoaded} = ${runtimeTemplate.basicFunction(
				"result, chunkIds, fn, priority",
				[
					"if(chunkIds) {",
					Template.indent([
						"priority = priority || 0;",
						"for(var i = deferred.length; i > 0 && deferred[i - 1][2] > priority; i--) deferred[i] = deferred[i - 1];",
						"deferred[i] = [chunkIds, fn, priority];",
						"return;"
					]),
					"}",
					"var notFulfilled = Infinity;",
					"for (var i = 0; i < deferred.length; i++) {",
					Template.indent([
						runtimeTemplate.destructureArray(
							["chunkIds", "fn", "priority"],
							"deferred[i]"
						),
						"var fulfilled = true;",
						"for (var j = 0; j < chunkIds.length; j++) {",
						Template.indent([
							`if ((priority & 1 === 0 || notFulfilled >= priority) && Object.keys(${
								RuntimeGlobals.onChunksLoaded
							}).every(${runtimeTemplate.returningFunction(
								`${RuntimeGlobals.onChunksLoaded}[key](chunkIds[j])`,
								"key"
							)})) {`,
							Template.indent(["chunkIds.splice(j--, 1);"]),
							"} else {",
							Template.indent([
								"fulfilled = false;",
								"if(priority < notFulfilled) notFulfilled = priority;"
							]),
							"}"
						]),
						"}",
						"if(fulfilled) {",
						Template.indent([
							"deferred.splice(i--, 1)",
							"var r = fn();",
							"if (r !== undefined) result = r;"
						]),
						"}"
					]),
					"}",
					"return result;"
				]
			)};`
		]);
	}
}

module.exports = OnChunksLoadedRuntimeModule;