webpack/lib/prefetch/ChunkPrefetchPreloadPlugin.js

Packs ECMAScript/CommonJs/AMD modules for the browser. Allows you to split your codebase into multiple bundles, which can be loaded on demand. Supports 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
	Author Tobias Koppers @sokra
*/

"use strict";

const RuntimeGlobals = require("../RuntimeGlobals");
const ChunkPrefetchFunctionRuntimeModule = require("./ChunkPrefetchFunctionRuntimeModule");
const ChunkPrefetchStartupRuntimeModule = require("./ChunkPrefetchStartupRuntimeModule");
const ChunkPrefetchTriggerRuntimeModule = require("./ChunkPrefetchTriggerRuntimeModule");
const ChunkPreloadTriggerRuntimeModule = require("./ChunkPreloadTriggerRuntimeModule");

/** @typedef {import("../Compiler")} Compiler */

const PLUGIN_NAME = "ChunkPrefetchPreloadPlugin";

/**
 * Adds runtime support for chunk prefetch and preload relationships discovered
 * in the chunk graph.
 */
class ChunkPrefetchPreloadPlugin {
	/**
	 * Registers compilation hooks that emit the runtime modules responsible for
	 * scheduling chunk prefetch and preload requests.
	 * @param {Compiler} compiler the compiler
	 * @returns {void}
	 */
	apply(compiler) {
		compiler.hooks.compilation.tap(PLUGIN_NAME, (compilation) => {
			compilation.hooks.additionalChunkRuntimeRequirements.tap(
				PLUGIN_NAME,
				(chunk, set, { chunkGraph }) => {
					if (chunkGraph.getNumberOfEntryModules(chunk) === 0) return;
					const startupChildChunks = chunk.getChildrenOfTypeInOrder(
						chunkGraph,
						"prefetchOrder"
					);
					if (startupChildChunks) {
						set.add(RuntimeGlobals.prefetchChunk);
						set.add(RuntimeGlobals.onChunksLoaded);
						set.add(RuntimeGlobals.exports);
						compilation.addRuntimeModule(
							chunk,
							new ChunkPrefetchStartupRuntimeModule(startupChildChunks)
						);
					}
				}
			);
			compilation.hooks.additionalTreeRuntimeRequirements.tap(
				PLUGIN_NAME,
				(chunk, set, { chunkGraph }) => {
					const chunkMap = chunk.getChildIdsByOrdersMap(chunkGraph);

					if (chunkMap.prefetch) {
						set.add(RuntimeGlobals.prefetchChunk);
						compilation.addRuntimeModule(
							chunk,
							new ChunkPrefetchTriggerRuntimeModule(chunkMap.prefetch)
						);
					}
					if (chunkMap.preload) {
						set.add(RuntimeGlobals.preloadChunk);
						compilation.addRuntimeModule(
							chunk,
							new ChunkPreloadTriggerRuntimeModule(chunkMap.preload)
						);
					}
					if (chunkMap.cssPreload) {
						// CSS-only preload (`parser.javascript.dynamicImportCssPreload`):
						// reuse `preloadChunk` — with no JS `preload` order the JS
						// handler is never registered, so only the CSS `.s` handler
						// fires (`<link rel="preload" as="style">`).
						set.add(RuntimeGlobals.preloadChunk);
						set.add(RuntimeGlobals.preloadChunkHandlers);
						compilation.addRuntimeModule(
							chunk,
							new ChunkPreloadTriggerRuntimeModule(
								chunkMap.cssPreload,
								"cssPreload"
							)
						);
					}
				}
			);
			compilation.hooks.runtimeRequirementInTree
				.for(RuntimeGlobals.prefetchChunk)
				.tap(PLUGIN_NAME, (chunk, set) => {
					compilation.addRuntimeModule(
						chunk,
						new ChunkPrefetchFunctionRuntimeModule(
							"prefetch",
							RuntimeGlobals.prefetchChunk,
							RuntimeGlobals.prefetchChunkHandlers
						)
					);
					set.add(RuntimeGlobals.prefetchChunkHandlers);
				});
			compilation.hooks.runtimeRequirementInTree
				.for(RuntimeGlobals.preloadChunk)
				.tap(PLUGIN_NAME, (chunk, set) => {
					compilation.addRuntimeModule(
						chunk,
						new ChunkPrefetchFunctionRuntimeModule(
							"preload",
							RuntimeGlobals.preloadChunk,
							RuntimeGlobals.preloadChunkHandlers
						)
					);
					set.add(RuntimeGlobals.preloadChunkHandlers);
				});
		});
	}
}

module.exports = ChunkPrefetchPreloadPlugin;