What is the time complexity of JavaScript methods? [closed]

Question

Is there any resource to know the time complexity of natively defined array and string methods in JavaScript? I have to do guess work while I am using them to solve algorithm, but I want to be sure about what is the time complexity of those functions?

Answer 1

This question has been answered previously:

Time Complexity for Javascript Methods in V8

In short, it's not specified and the time complexity for common JS methods can differ between browsers.

Worse yet, some methods might not even exist or will behave differently between different browsers and browser versions!