Performance Test
Write simple vanilla JS performance tests.
Read this article to learn more about this technique works.
If you just want to log results to the console
console.time('My awesome performance test!');
// Do some JS stuff...
console.timeEnd('My awesome performance test!');
// This will log "My awesome performance test!: 1234.567ms" (with the actual time, of course)
If you want to render the results into the DOM/UI
var start = performance.now();
// Do some JS stuff...
var end = performance.now();
console.log('This took ' + (end - start) + 'ms to complete');