feat(scripts): add "lighthouse" subcommand for gathering perf metrics

packages/liferay-npm-scripts/package.json

@@ -36,6 +36,7 @@
 		"babel-jest": "^25.1.0",
 		"babel-loader": "8.0.6",
 		"babel-plugin-transform-react-remove-prop-types": "0.4.24",
+		"chrome-launcher": "0.12.0",
 		"cosmiconfig": "^6.0.0",
 		"cross-env": "^7.0.0",
 		"cross-spawn": "7.0.1",
@@ -55,6 +56,7 @@
 		"liferay-npm-bundler": "2.18.2",
 		"liferay-npm-bundler-preset-liferay-dev": "4.2.5",
 		"liferay-theme-tasks": "9.4.3",
+		"lighthouse": "5.6.0",
 		"metal-tools-soy": "4.3.2",
 		"minimist": "^1.2.0",
 		"prettier": "1.19.1",

packages/liferay-npm-scripts/src/index.js

@@ -55,6 +55,10 @@ module.exports = async function() {
 			require('./scripts/format')({check: true});
 		},
 
+		async lighthouse() {
+			await require('./scripts/lighthouse')();
+		},
+
 		async lint() {
 			await require('./scripts/lint')();
 		},

packages/liferay-npm-scripts/src/scripts/lighthouse.js

@@ -0,0 +1,51 @@
+/**
+ * SPDX-FileCopyrightText: © 2019 Liferay, Inc. <https://liferay.com>
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+const launcher = require('chrome-launcher');
+const lh = require('lighthouse');
+const path = require('path');
+
+/**
+ * Wrapper for the Lighthouse performance auditing command-line tool.
+ *
+ * @see https://developers.google.com/web/tools/lighthouse
+ */
+async function lighthouse() {
+	const chromeFlags = ['--headless'];
+	const chromePath = process.env.CHROME_PATH
+		? path.resolve(process.env.CHROME_PATH)
+		: undefined;
+
+	const logLevel = process.env.DEBUG ? 'verbose' : 'error';
+
+	const launcherOptions = {
+		chromeFlags,
+		chromePath,
+		logLevel
+	};
+
+	const chrome = await launcher.launch(launcherOptions);
+
+	const url = process.env.PORTAL_URL || 'http://localhost:8080/';
+
+	const lighthouseOptions = {
+		logLevel,
+		onlyCategories: ['performance'],
+		port: chrome.port
+	};
+
+	const config = undefined;
+
+	const results = await lh(url, lighthouseOptions, config);
+
+	await chrome.kill();
+
+	/* eslint-disable no-console */
+	console.log(results.lhr); // "JS-consumable output"
+	console.log(results.report); // "HTML/JSON/CSV as a string"
+	console.log(results.artifacts); // "trace/screenshots/other"
+}
+
+module.exports = lighthouse;