webpack/lib/runtime/GetWorkletBootstrapRuntimeModule.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 sheo13666q
*/

"use strict";

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

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

/**
 * Provides a single object URL (one per base URI) for the worklet bootstrap
 * script. A worklet global scope has no `self` and no `location`; this script
 * sets them up before the emitted chunks — which assume a worker-like scope —
 * are added via `addModule`. Deduping by base URI avoids leaking a new object
 * URL per worklet.
 */
class GetWorkletBootstrapRuntimeModule extends RuntimeModule {
	constructor() {
		super("get worklet bootstrap", RuntimeModule.STAGE_ATTACH);
	}

	/**
	 * Generates runtime code for this runtime module.
	 * @returns {string | null} runtime code
	 */
	generate() {
		const { getWorkletBootstrap, baseURI } = RuntimeGlobals;
		const { runtimeTemplate } = /** @type {Compilation} */ (this.compilation);
		// The arrow inside the blob string is fine — it runs in the worklet (always
		// a module scope); the surrounding functions must respect `output.environment`.
		const getter = runtimeTemplate.basicFunction("", [
			`var base = ${baseURI};`,
			"if (!cache.has(base)) {",
			Template.indent([
				"var script = [",
				Template.indent([
					// worklet scopes have no `self`; chunks assume a worker-like scope
					'"globalThis.self = globalThis.self || globalThis;",',
					// some runtime modules read `location`; forward the document base
					'"globalThis.location = " + JSON.stringify(base) + ";"'
				]),
				'].join("\\n");',
				'cache.set(base, URL.createObjectURL(new Blob([script], { type: "text/javascript" })));'
			]),
			"}",
			"return cache.get(base);"
		]);
		return `${getWorkletBootstrap} = (${runtimeTemplate.basicFunction("", [
			"var cache = new Map();",
			`return ${getter};`
		])})();`;
	}
}

module.exports = GetWorkletBootstrapRuntimeModule;