normalize-url/index.js

'use strict';
// TODO: Use the `URL` global when targeting Node.js 10
const URLParser = typeof URL === 'undefined' ? require('url').URL : URL;

const testParameter = (name, filters) => {
	return filters.some(filter => filter instanceof RegExp ? filter.test(name) : filter === name);
};

module.exports = (urlString, options) => {
	options = {
		defaultProtocol: 'http:',
		normalizeProtocol: true,
		forceHttp: false,
		forceHttps: false,
		stripAuthentication: true,
		stripHash: false,
		stripWWW: true,
		removeQueryParameters: [/^utm_\w+/i],
		removeTrailingSlash: true,
		removeDirectoryIndex: false,
		sortQueryParameters: true,
		...options
	};

	// TODO: Remove this at some point in the future
	if (Reflect.has(options, 'normalizeHttps')) {
		throw new Error('options.normalizeHttps is renamed to options.forceHttp');
	}

	if (Reflect.has(options, 'normalizeHttp')) {
		throw new Error('options.normalizeHttp is renamed to options.forceHttps');
	}

	if (Reflect.has(options, 'stripFragment')) {
		throw new Error('options.stripFragment is renamed to options.stripHash');
	}

	urlString = urlString.trim();

	const hasRelativeProtocol = urlString.startsWith('//');
	const isRelativeUrl = !hasRelativeProtocol && /^\.*\//.test(urlString);

	// Prepend protocol
	if (!isRelativeUrl) {
		urlString = urlString.replace(/^(?!(?:\w+:)?\/\/)|^\/\//, options.defaultProtocol);
	}

	const urlObj = new URLParser(urlString);

	if (options.forceHttp && options.forceHttps) {
		throw new Error('The `forceHttp` and `forceHttps` options cannot be used together');
	}

	if (options.forceHttp && urlObj.protocol === 'https:') {
		urlObj.protocol = 'http:';
	}

	if (options.forceHttps && urlObj.protocol === 'http:') {
		urlObj.protocol = 'https:';
	}

	// Remove auth
	if (options.stripAuthentication) {
		urlObj.username = '';
		urlObj.password = '';
	}

	// Remove hash
	if (options.stripHash) {
		urlObj.hash = '';
	}

	// Remove duplicate slashes if not preceded by a protocol
	if (urlObj.pathname) {
		// TODO: Use the following instead when targeting Node.js 10
		// `urlObj.pathname = urlObj.pathname.replace(/(?<!https?:)\/{2,}/g, '/');`
		urlObj.pathname = urlObj.pathname.replace(/((?!:).|^)\/{2,}/g, (_, p1) => {
			if (/^(?!\/)/g.test(p1)) {
				return `${p1}/`;
			}
			return '/';
		});
	}

	// Decode URI octets
	if (urlObj.pathname) {
		urlObj.pathname = decodeURI(urlObj.pathname);
	}

	// Remove directory index
	if (options.removeDirectoryIndex === true) {
		options.removeDirectoryIndex = [/^index\.[a-z]+$/];
	}

	if (Array.isArray(options.removeDirectoryIndex) && options.removeDirectoryIndex.length > 0) {
		let pathComponents = urlObj.pathname.split('/');
		const lastComponent = pathComponents[pathComponents.length - 1];

		if (testParameter(lastComponent, options.removeDirectoryIndex)) {
			pathComponents = pathComponents.slice(0, pathComponents.length - 1);
			urlObj.pathname = pathComponents.slice(1).join('/') + '/';
		}
	}

	if (urlObj.hostname) {
		// Remove trailing dot
		urlObj.hostname = urlObj.hostname.replace(/\.$/, '');

		// Remove `www.`
		if (options.stripWWW && /^www\.([a-z\-\d]{2,63})\.([a-z.]{2,5})$/.test(urlObj.hostname)) {
			// Each label should be max 63 at length (min: 2).
			// The extension should be max 5 at length (min: 2).
			// Source: https://en.wikipedia.org/wiki/Hostname#Restrictions_on_valid_host_names
			urlObj.hostname = urlObj.hostname.replace(/^www\./, '');
		}
	}

	// Remove query unwanted parameters
	if (Array.isArray(options.removeQueryParameters)) {
		for (const key of [...urlObj.searchParams.keys()]) {
			if (testParameter(key, options.removeQueryParameters)) {
				urlObj.searchParams.delete(key);
			}
		}
	}

	// Sort query parameters
	if (options.sortQueryParameters) {
		urlObj.searchParams.sort();
	}

	if (options.removeTrailingSlash) {
		urlObj.pathname = urlObj.pathname.replace(/\/$/, '');
	}

	// Take advantage of many of the Node `url` normalizations
	urlString = urlObj.toString();

	// Remove ending `/`
	if ((options.removeTrailingSlash || urlObj.pathname === '/') && urlObj.hash === '') {
		urlString = urlString.replace(/\/$/, '');
	}

	// Restore relative protocol, if applicable
	if (hasRelativeProtocol && !options.normalizeProtocol) {
		urlString = urlString.replace(/^http:\/\//, '//');
	}

	// Remove http/https
	if (options.stripProtocol) {
		urlString = urlString.replace(/^(?:https?:)?\/\//, '');
	}

	return urlString;
};