happy-dom/src/module/ModuleFactory.ts

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. It includes many web standards from WHATWG DOM and HTML.

import { URL } from 'url';
import IModule from './IModule.js';
import * as PropertySymbol from '../PropertySymbol.js';
import CSSModule from './CSSModule.js';
import JSONModule from './JSONModule.js';
import UnresolvedModule from './UnresolvedModule.js';
import WindowBrowserContext from '../window/WindowBrowserContext.js';
import ResourceFetch from '../fetch/ResourceFetch.js';
import ECMAScriptModule from './ECMAScriptModule.js';
import BrowserWindow from '../window/BrowserWindow.js';
import Location from '../location/Location.js';

/**
 * Module factory.
 */
export default class ModuleFactory {
	/**
	 * Fetches the source code of the module from the given URL and creates a new module instance.
	 *
	 * @param window Window.
	 * @param parentURL Parent URL.
	 * @param url Module URL.
	 * @param [options] Options.
	 * @param [options.with] Options.
	 * @param [options.with.type] Module type.
	 */
	public static async getModule(
		window: BrowserWindow,
		parentURL: URL | Location,
		url: string,
		options?: { with?: { type?: string } }
	): Promise<IModule> {
		const absoluteURL = this.getURL(window, parentURL, url);
		const absoluteURLString = absoluteURL.href;
		const type = options?.with?.type || 'esm';

		if (type !== 'esm' && type !== 'css' && type !== 'json') {
			throw new window.TypeError(
				`Failed to import module "${absoluteURL}" from "${parentURL}": Unkown type "${type}"`
			);
		}

		const cached = <IModule>window[PropertySymbol.modules][type].get(absoluteURLString);

		if (cached) {
			if (cached instanceof UnresolvedModule) {
				await new Promise((resolve, reject) => {
					cached.addResolveListener(resolve, reject);
				});
				return <IModule>window[PropertySymbol.modules][type].get(absoluteURLString);
			}
			return cached;
		}
		const browserFrame = new WindowBrowserContext(window).getBrowserFrame();

		if (!browserFrame) {
			throw new window.TypeError(
				`Failed to import module "${absoluteURL}" from "${parentURL}": Window is closed and is no longer attached to a frame`
			);
		}

		const unresolvedModule = new UnresolvedModule(window, absoluteURL);

		window[PropertySymbol.modules][type].set(absoluteURLString, unresolvedModule);

		const resourceFetch = new ResourceFetch(window);
		let source: string;
		try {
			source = await resourceFetch.fetch(absoluteURL, 'module');
		} catch (error) {
			unresolvedModule.resolve(error);
			throw error;
		}
		let module: IModule;

		switch (type) {
			case 'json':
				module = new JSONModule(window, absoluteURL, source);
				break;
			case 'css':
				module = new CSSModule(window, absoluteURL, source);
				break;
			case 'esm':
				module = new ECMAScriptModule(window, absoluteURL, source);
				break;
		}

		window[PropertySymbol.modules][type].set(absoluteURLString, module);

		unresolvedModule.resolve();

		return module;
	}

	/**
	 * Returns module URL based on parent URL and the import map.
	 *
	 * @param window Window.
	 * @param parentURL Parent URL.
	 * @param url Module URL.
	 */
	private static getURL(window: BrowserWindow, parentURL: URL | Location, url: string): URL {
		const parentURLString = parentURL.href;
		const absoluteURL = new URL(url, parentURLString);
		const absoluteURLString = absoluteURL.href;
		const importMap = window[PropertySymbol.moduleImportMap];

		if (!importMap) {
			return absoluteURL;
		}

		if (importMap.scopes) {
			for (const scope of importMap.scopes) {
				if (parentURLString.includes(scope.scope)) {
					for (const rule of scope.rules) {
						if (absoluteURLString.startsWith(rule.from)) {
							return new URL(rule.to + absoluteURLString.replace(rule.from, ''));
						}
					}
				}
			}
		}

		if (importMap.imports) {
			for (const rule of importMap.imports) {
				if (absoluteURLString.startsWith(rule.from)) {
					return new URL(rule.to + absoluteURLString.replace(rule.from, ''));
				}
			}
		}

		return absoluteURL;
	}
}