What are some tools that can be used to measure and analyze JavaScript performance?

TL;DR

To measure and analyze JavaScript performance, you can use tools like Chrome DevTools, Lighthouse, WebPageTest, and JSPerf. Chrome DevTools provides a Performance panel for profiling, Lighthouse offers audits for performance metrics, WebPageTest allows for detailed performance testing, and JSPerf helps in comparing the performance of different JavaScript snippets.

Tools to measure and analyze JavaScript performance

Chrome DevTools

Chrome DevTools is a set of web developer tools built directly into the Google Chrome browser. It provides a Performance panel that allows you to record and analyze the runtime performance of your web application.

Open Chrome DevTools by pressing F12 or Ctrl+Shift+I
Navigate to the Performance panel
Click the "Record" button to start profiling
Interact with your web application to capture performance data
Click the "Stop" button to end profiling and analyze the results

Lighthouse

Lighthouse is an open-source, automated tool for improving the quality of web pages. It provides audits for performance, accessibility, progressive web apps, SEO, and more.

Open Chrome DevTools
Navigate to the Lighthouse panel
Select the categories you want to audit (e.g., Performance)
Click the "Generate report" button
Review the generated report for performance insights and recommendations

WebPageTest

WebPageTest is a free online tool that provides detailed performance testing of web pages. It allows you to run tests from multiple locations around the world using real browsers.

Go to WebPageTest
Enter the URL of the web page you want to test
Select the test location and browser
Click the "Start Test" button
Review the detailed performance report, including metrics like load time, time to first byte, and more

JSPerf

JSPerf is a tool for comparing the performance of different JavaScript snippets. It allows you to create and run benchmarks to see which code performs better.

Go to JSPerf
Create a new test case by entering different JavaScript snippets
Run the benchmark to compare the performance of the snippets
Review the results to see which snippet performs better