How and how can you test the speed of js on a web page?

Question

JavaScript

Actually, how can you test the performance of js code on a page?
I myself use Timeline in chrome, but maybe there are some more advanced tools for checking the speed of work.
I would like something like a phone emulator with the same virtual hardware.

Answer 1

Yes, I have.

console.time('id');
...
console.timeEnd('id');

There is an excellent article on Habré about the console.
As for mobile phones - everything is simple, you can put it on a virtual machine, yes. Although not tested.