webpack/lib/runtime/ToBinaryRuntimeModule.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 RuntimeGlobals = require("../RuntimeGlobals");
const RuntimeModule = require("../RuntimeModule");
const Template = require("../Template");

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

class ToBinaryRuntimeModule extends RuntimeModule {
	constructor() {
		super("to binary");
	}

	/**
	 * @returns {string | null} runtime code
	 */
	generate() {
		const compilation = /** @type {Compilation} */ (this.compilation);
		const fn = RuntimeGlobals.toBinary;
		const { runtimeTemplate } = compilation;

		// Inspired by esbuild

		const isNodePlatform = compilation.compiler.platform.node;
		const isWebPlatform = compilation.compiler.platform.web;
		const isNeutralPlatform = runtimeTemplate.isNeutralPlatform();
		const toImmutableBytes = runtimeTemplate.basicFunction("value", [
			runtimeTemplate.destructureObject(["buffer"], "value"),
			`${runtimeTemplate.renderConst()} throwErr = ${runtimeTemplate.basicFunction("", ["throw new TypeError('ArrayBuffer is immutable');"])};`,
			"Object.defineProperties(buffer, { immutable: { value: true },  resize: { value: throwErr }, transfer: { value: throwErr }, transferToFixedLength: { value: throwErr } });",
			"Object.freeze(buffer);",
			"return value;"
		]);

		return Template.asString([
			"// define to binary helper",
			`${runtimeTemplate.renderConst()} toImmutableBytes = ${toImmutableBytes}`,
			`${fn} = ${isNeutralPlatform ? "typeof Buffer !== 'undefined' ? " : ""}${
				isNodePlatform || isNeutralPlatform
					? `${runtimeTemplate.returningFunction("toImmutableBytes(new Uint8Array(Buffer.from(base64, 'base64')))", "base64")}`
					: ""
			} ${isNeutralPlatform ? ": " : ""}${
				isWebPlatform || isNeutralPlatform
					? `(${runtimeTemplate.basicFunction("", [
							`${runtimeTemplate.renderConst()} table = new Uint8Array(128);`,
							"for (var i = 0; i < 64; i++) table[i < 26 ? i + 65 : i < 52 ? i + 71 : i < 62 ? i - 4 : i * 4 - 205] = i;",
							`return ${runtimeTemplate.basicFunction("base64", [
								`${runtimeTemplate.renderConst()} n = base64.length, bytes = new Uint8Array((n - (base64[n - 1] == '=') - (base64[n - 2] == '=')) * 3 / 4 | 0);`,
								"for (var i = 0, j = 0; i < n;) {",
								Template.indent([
									`${runtimeTemplate.renderConst()} c0 = table[base64.charCodeAt(i++)], c1 = table[base64.charCodeAt(i++)];`,
									`${runtimeTemplate.renderConst()} c2 = table[base64.charCodeAt(i++)], c3 = table[base64.charCodeAt(i++)];`,
									"bytes[j++] = (c0 << 2) | (c1 >> 4);",
									"bytes[j++] = (c1 << 4) | (c2 >> 2);",
									"bytes[j++] = (c2 << 6) | c3;"
								]),
								"}",
								"return toImmutableBytes(bytes)"
							])}`
						])})();`
					: ""
			}`
		]);
	}
}

module.exports = ToBinaryRuntimeModule;