webpack/lib/dependencies/URLPlugin.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 Ivan Kopeykin @vankop
*/

"use strict";

const { pathToFileURL } = require("url");
const BasicEvaluatedExpression = require("../javascript/BasicEvaluatedExpression");
const { approve } = require("../javascript/JavascriptParserHelpers");
const InnerGraph = require("../optimize/InnerGraph");
const URLDependency = require("./URLDependency");

/** @typedef {import("estree").NewExpression} NewExpressionNode */
/** @typedef {import("../Compiler")} Compiler */
/** @typedef {import("../NormalModule")} NormalModule */
/** @typedef {import("../javascript/JavascriptParser")} JavascriptParser */

class URLPlugin {
	/**
	 * @param {Compiler} compiler compiler
	 */
	apply(compiler) {
		compiler.hooks.compilation.tap(
			"URLPlugin",
			(compilation, { normalModuleFactory }) => {
				compilation.dependencyFactories.set(URLDependency, normalModuleFactory);
				compilation.dependencyTemplates.set(
					URLDependency,
					new URLDependency.Template()
				);

				/**
				 * @param {NormalModule} module module
				 * @returns {URL} file url
				 */
				const getUrl = module => {
					return pathToFileURL(module.resource);
				};
				/**
				 * @param {JavascriptParser} parser parser
				 * @param {object} parserOptions options
				 */
				const parserCallback = (parser, parserOptions) => {
					if (parserOptions.url === false) return;
					const relative = parserOptions.url === "relative";

					/**
					 * @param {NewExpressionNode} expr expression
					 * @returns {undefined | string} request
					 */
					const getUrlRequest = expr => {
						if (expr.arguments.length !== 2) return;

						const [arg1, arg2] = expr.arguments;

						if (
							arg2.type !== "MemberExpression" ||
							arg1.type === "SpreadElement"
						)
							return;

						const chain = parser.extractMemberExpressionChain(arg2);

						if (
							chain.members.length !== 1 ||
							chain.object.type !== "MetaProperty" ||
							chain.object.meta.name !== "import" ||
							chain.object.property.name !== "meta" ||
							chain.members[0] !== "url"
						)
							return;

						const request = parser.evaluateExpression(arg1).asString();

						return request;
					};

					parser.hooks.canRename.for("URL").tap("URLPlugin", approve);
					parser.hooks.evaluateNewExpression
						.for("URL")
						.tap("URLPlugin", expr => {
							const request = getUrlRequest(expr);
							if (!request) return;
							const url = new URL(request, getUrl(parser.state.module));

							return new BasicEvaluatedExpression()
								.setString(url.toString())
								.setRange(expr.range);
						});
					parser.hooks.new.for("URL").tap("URLPlugin", _expr => {
						const expr = /** @type {NewExpressionNode} */ (_expr);

						const request = getUrlRequest(expr);

						if (!request) return;

						const [arg1, arg2] = expr.arguments;
						const dep = new URLDependency(
							request,
							[arg1.range[0], arg2.range[1]],
							expr.range,
							relative
						);
						dep.loc = expr.loc;
						parser.state.current.addDependency(dep);
						InnerGraph.onUsage(parser.state, e => (dep.usedByExports = e));
						return true;
					});
					parser.hooks.isPure.for("NewExpression").tap("URLPlugin", _expr => {
						const expr = /** @type {NewExpressionNode} */ (_expr);
						const { callee } = expr;
						if (callee.type !== "Identifier") return;
						const calleeInfo = parser.getFreeInfoFromVariable(callee.name);
						if (!calleeInfo || calleeInfo.name !== "URL") return;

						const request = getUrlRequest(expr);

						if (request) return true;
					});
				};

				normalModuleFactory.hooks.parser
					.for("javascript/auto")
					.tap("URLPlugin", parserCallback);

				normalModuleFactory.hooks.parser
					.for("javascript/esm")
					.tap("URLPlugin", parserCallback);
			}
		);
	}
}

module.exports = URLPlugin;