webpack/lib/wasm-async/UniversalCompileAsyncWasmPlugin.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 Alexander Akait @alexander-akait
*/

"use strict";

const { WEBASSEMBLY_MODULE_TYPE_ASYNC } = require("../ModuleTypeConstants");
const RuntimeGlobals = require("../RuntimeGlobals");
const Template = require("../Template");
const AsyncWasmLoadingRuntimeModule = require("../wasm-async/AsyncWasmLoadingRuntimeModule");

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

const PLUGIN_NAME = "UniversalCompileAsyncWasmPlugin";

class UniversalCompileAsyncWasmPlugin {
	/**
	 * Apply the plugin
	 * @param {Compiler} compiler the compiler instance
	 * @returns {void}
	 */
	apply(compiler) {
		compiler.hooks.thisCompilation.tap(PLUGIN_NAME, compilation => {
			const globalWasmLoading = compilation.outputOptions.wasmLoading;
			/**
			 * @param {Chunk} chunk chunk
			 * @returns {boolean} true, if wasm loading is enabled for the chunk
			 */
			const isEnabledForChunk = chunk => {
				const options = chunk.getEntryOptions();
				const wasmLoading =
					options && options.wasmLoading !== undefined
						? options.wasmLoading
						: globalWasmLoading;
				return wasmLoading === "universal";
			};
			const generateBeforeInstantiateStreaming = () =>
				Template.asString([
					"if (!useFetch) {",
					Template.indent(["return fallback();"]),
					"}"
				]);
			/**
			 * @param {string} path path
			 * @returns {string} code
			 */
			const generateBeforeLoadBinaryCode = path =>
				Template.asString([
					"var useFetch = typeof document !== 'undefined' || typeof self !== 'undefined';",
					`var wasmUrl = ${path};`
				]);
			/**
			 * @type {(path: string) => string}
			 */
			const generateLoadBinaryCode = () =>
				Template.asString([
					"(useFetch",
					Template.indent([
						`? fetch(new URL(wasmUrl, ${compilation.outputOptions.importMetaName}.url))`
					]),
					Template.indent([
						": Promise.all([import('fs'), import('url')]).then(([{ readFile }, { URL }]) => new Promise((resolve, reject) => {",
						Template.indent([
							`readFile(new URL(wasmUrl, ${compilation.outputOptions.importMetaName}.url), (err, buffer) => {`,
							Template.indent([
								"if (err) return reject(err);",
								"",
								"// Fake fetch response",
								"resolve({",
								Template.indent(["arrayBuffer() { return buffer; }"]),
								"});"
							]),
							"});"
						]),
						"})))"
					])
				]);

			compilation.hooks.runtimeRequirementInTree
				.for(RuntimeGlobals.instantiateWasm)
				.tap(PLUGIN_NAME, (chunk, set, { chunkGraph }) => {
					if (!isEnabledForChunk(chunk)) return;
					if (
						!chunkGraph.hasModuleInGraph(
							chunk,
							m => m.type === WEBASSEMBLY_MODULE_TYPE_ASYNC
						)
					) {
						return;
					}
					compilation.addRuntimeModule(
						chunk,
						new AsyncWasmLoadingRuntimeModule({
							generateBeforeLoadBinaryCode,
							generateLoadBinaryCode,
							generateBeforeInstantiateStreaming,
							supportsStreaming: true
						})
					);
				});
		});
	}
}

module.exports = UniversalCompileAsyncWasmPlugin;