webpack/lib/asset/AssetSourceGenerator.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 Sergey Melyukov @smelukov
*/

"use strict";

const { RawSource } = require("webpack-sources");
const ConcatenationScope = require("../ConcatenationScope");
const Generator = require("../Generator");
const RuntimeGlobals = require("../RuntimeGlobals");

/** @typedef {import("webpack-sources").Source} Source */
/** @typedef {import("../Generator").GenerateContext} GenerateContext */
/** @typedef {import("../Module").ConcatenationBailoutReasonContext} ConcatenationBailoutReasonContext */
/** @typedef {import("../NormalModule")} NormalModule */

const TYPES = new Set(["javascript"]);

class AssetSourceGenerator extends Generator {
	/**
	 * @param {NormalModule} module module for which the code should be generated
	 * @param {GenerateContext} generateContext context for generate
	 * @returns {Source} generated code
	 */
	generate(
		module,
		{ concatenationScope, chunkGraph, runtimeTemplate, runtimeRequirements }
	) {
		const originalSource = module.originalSource();

		if (!originalSource) {
			return new RawSource("");
		}

		const content = originalSource.source();

		let encodedSource;
		if (typeof content === "string") {
			encodedSource = content;
		} else {
			encodedSource = content.toString("utf-8");
		}

		let sourceContent;
		if (concatenationScope) {
			concatenationScope.registerNamespaceExport(
				ConcatenationScope.NAMESPACE_OBJECT_EXPORT
			);
			sourceContent = `${runtimeTemplate.supportsConst() ? "const" : "var"} ${
				ConcatenationScope.NAMESPACE_OBJECT_EXPORT
			} = ${JSON.stringify(encodedSource)};`;
		} else {
			runtimeRequirements.add(RuntimeGlobals.module);
			sourceContent = `${RuntimeGlobals.module}.exports = ${JSON.stringify(
				encodedSource
			)};`;
		}
		return new RawSource(sourceContent);
	}

	/**
	 * @param {NormalModule} module module for which the bailout reason should be determined
	 * @param {ConcatenationBailoutReasonContext} context context
	 * @returns {string | undefined} reason why this module can't be concatenated, undefined when it can be concatenated
	 */
	getConcatenationBailoutReason(module, context) {
		return undefined;
	}

	/**
	 * @param {NormalModule} module fresh module
	 * @returns {Set<string>} available types (do not mutate)
	 */
	getTypes(module) {
		return TYPES;
	}

	/**
	 * @param {NormalModule} module the module
	 * @param {string=} type source type
	 * @returns {number} estimate size of the module
	 */
	getSize(module, type) {
		const originalSource = module.originalSource();

		if (!originalSource) {
			return 0;
		}

		// Example: m.exports="abcd"
		return originalSource.size() + 12;
	}
}

module.exports = AssetSourceGenerator;