webpack/lib/runtime/PublicPathRuntimeModule.js

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
*/

"use strict";

const RuntimeGlobals = require("../RuntimeGlobals");
const RuntimeModule = require("../RuntimeModule");
const Template = require("../Template");
const JavascriptModulesPlugin = require("../javascript/JavascriptModulesPlugin");
const { getUndoPath } = require("../util/identifier");

/** @typedef {import("../../declarations/WebpackOptions").Output} OutputOptions */
/** @typedef {import("../../declarations/WebpackOptions").PublicPath} PublicPathOptions */
/** @typedef {import("../Compilation")} Compilation */
/** @typedef {import("../RuntimeTemplate")} RuntimeTemplate */

class PublicPathRuntimeModule extends RuntimeModule {
	/**
	 * @returns {ReadonlyArray<string> | null} requirements
	 */
	getRuntimeRequirements() {
		const { compilation } = this;
		const { publicPath, scriptType } = compilation.outputOptions;
		if (publicPath !== "auto" || scriptType === "module") return null;

		return [RuntimeGlobals.global];
	}

	constructor() {
		super("publicPath", 5);
	}

	/**
	 * @returns {string} runtime code
	 */
	generate() {
		const { compilation } = this;
		const {
			publicPath,
			scriptType,
			importFunctionName
		} = compilation.outputOptions;
		if (publicPath === "auto") {
			const chunkName = compilation.getPath(
				JavascriptModulesPlugin.getChunkFilenameTemplate(
					this.chunk,
					compilation.outputOptions
				),
				{
					chunk: this.chunk,
					contentHashType: "javascript"
				}
			);
			const undoPath = getUndoPath(chunkName, false);
			return Template.asString([
				"var scriptUrl;",
				scriptType === "module"
					? `if (typeof ${importFunctionName}.meta.url === "string") scriptUrl = ${importFunctionName}.meta.url`
					: Template.asString([
							`var document = ${RuntimeGlobals.global}.document;`,
							"if (document) {",
							Template.indent([
								`if (document.currentScript)`,
								Template.indent(`scriptUrl = document.currentScript.src`),
								"if (!scriptUrl) {",
								Template.indent([
									'var scripts = document.getElementsByTagName("script");',
									"if(scripts.length) scriptUrl = scripts[scripts.length - 1].src"
								]),
								"}"
							]),
							"}"
					  ]),
				"// When supporting browsers where an automatic publicPath is not supported you must specify an output.publicPath manually via configuration",
				'// or pass an empty string ("") and set the __webpack_public_path__ variable from your code to use your own logic.',
				'if (!scriptUrl) throw new Error("Automatic publicPath is not supported in this browser");',
				'scriptUrl = scriptUrl.replace(/#.*$/, "").replace(/\\?.*$/, "").replace(/\\/[^\\/]+$/, "/");',
				!undoPath
					? `${RuntimeGlobals.publicPath} = scriptUrl;`
					: `${RuntimeGlobals.publicPath} = scriptUrl + ${JSON.stringify(
							undoPath
					  )};`
			]);
		} else {
			return `${RuntimeGlobals.publicPath} = ${this.definePath(publicPath)};`;
		}
	}

	/**
	 * @param {PublicPathOptions} publicPath public path
	 * @returns {string} runtime code
	 */
	definePath(publicPath) {
		return JSON.stringify(
			this.compilation.getPath(publicPath || "", {
				hash: this.compilation.hash || "XXXX"
			})
		);
	}
}

module.exports = PublicPathRuntimeModule;