/** * @fileoverview Disallow using Date for timing in performance sensitive code * * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ "use strict"; module.exports = { meta: { docs: { url: "https://firefox-source-docs.mozilla.org/code-quality/lint/linters/eslint-plugin-mozilla/avoid-Date-timing.html", }, messages: { usePerfNow: "use performance.now() instead of Date.now() for timing measurements", }, schema: [], type: "problem", }, create(context) { return { CallExpression(node) { let callee = node.callee; if ( callee.type !== "MemberExpression" || callee.object.type !== "Identifier" || callee.object.name !== "Date" || callee.property.type !== "Identifier" || callee.property.name !== "now" ) { return; } context.report({ node, messageId: "usePerfNow", }); }, NewExpression(node) { let callee = node.callee; if ( callee.type !== "Identifier" || callee.name !== "Date" || node.arguments.length ) { return; } context.report({ node, messageId: "usePerfNow", }); }, }; }, };