webpack/lib/EvalSourceMapDevToolModuleTemplatePlugin.js

Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support 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 { RawSource } = require("webpack-sources");
const ModuleFilenameHelpers = require("./ModuleFilenameHelpers");

const cache = new WeakMap();

class EvalSourceMapDevToolModuleTemplatePlugin {
	constructor(compilation, options) {
		this.compilation = compilation;
		this.sourceMapComment =
			options.append || "//# sourceURL=[module]\n//# sourceMappingURL=[url]";
		this.moduleFilenameTemplate =
			options.moduleFilenameTemplate ||
			"webpack://[namespace]/[resource-path]?[hash]";
		this.namespace = options.namespace || "";
		this.options = options;
	}

	apply(moduleTemplate) {
		const self = this;
		const options = this.options;
		const matchModule = ModuleFilenameHelpers.matchObject.bind(
			ModuleFilenameHelpers,
			options
		);
		moduleTemplate.hooks.module.tap(
			"EvalSourceMapDevToolModuleTemplatePlugin",
			(source, module) => {
				const cachedSource = cache.get(source);
				if (cachedSource !== undefined) {
					return cachedSource;
				}

				if (!matchModule(module.resource)) {
					return source;
				}

				/** @type {{ [key: string]: TODO; }} */
				let sourceMap;
				let content;
				if (source.sourceAndMap) {
					const sourceAndMap = source.sourceAndMap(options);
					sourceMap = sourceAndMap.map;
					content = sourceAndMap.source;
				} else {
					sourceMap = source.map(options);
					content = source.source();
				}
				if (!sourceMap) {
					return source;
				}

				// Clone (flat) the sourcemap to ensure that the mutations below do not persist.
				sourceMap = Object.keys(sourceMap).reduce((obj, key) => {
					obj[key] = sourceMap[key];
					return obj;
				}, {});
				const modules = sourceMap.sources.map(source => {
					const module = self.compilation.findModule(source);
					return module || source;
				});
				let moduleFilenames = modules.map(module => {
					return ModuleFilenameHelpers.createFilename(
						module,
						{
							moduleFilenameTemplate: self.moduleFilenameTemplate,
							namespace: self.namespace
						},
						moduleTemplate.runtimeTemplate.requestShortener
					);
				});
				moduleFilenames = ModuleFilenameHelpers.replaceDuplicates(
					moduleFilenames,
					(filename, i, n) => {
						for (let j = 0; j < n; j++) filename += "*";
						return filename;
					}
				);
				sourceMap.sources = moduleFilenames;
				sourceMap.sourceRoot = options.sourceRoot || "";
				sourceMap.file = `${module.id}.js`;

				const footer =
					self.sourceMapComment.replace(
						/\[url\]/g,
						`data:application/json;charset=utf-8;base64,${Buffer.from(
							JSON.stringify(sourceMap),
							"utf8"
						).toString("base64")}`
					) + `\n//# sourceURL=webpack-internal:///${module.id}\n`; // workaround for chrome bug

				const evalSource = new RawSource(
					`eval(${JSON.stringify(content + footer)});`
				);

				cache.set(source, evalSource);

				return evalSource;
			}
		);
		moduleTemplate.hooks.hash.tap(
			"EvalSourceMapDevToolModuleTemplatePlugin",
			hash => {
				hash.update("eval-source-map");
				hash.update("2");
			}
		);
	}
}
module.exports = EvalSourceMapDevToolModuleTemplatePlugin;