it should be for not if, the if should be nested in the for loop, first if should be i === 0 and second should be i === 1

could you perhaps teach me other tips and tricks in js other than

The way I see it, some use cases:

Aliasing other functions. For example log = console.log would allow you to get rid of typing console every time.
Because why not / code golf purposes.
Some more advanced use cases like String.prototype.map = Array.prototype.map, that would allow you to use map on strings directly.
It looks cooler.

if you dont mind ofcourse