Why is looping through an Array so much faster than JavaScript's native `indexOf`?

Question

Why is looping through an Array so much faster than JavaScript\'s native indexOf? Is there an error or something that I\'m not accounting for? I expected nati

Answer 1

indexOf does a bunch of type-checking and validation that the for loop and while loop ignore.

Here's the indexOf algorithm:

https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/indexOf

Edit: My guess is indexOf is faster for big arrays because it caches the length of the array before looping through it.