@benbrnpetit for larger datasets push will be more performant than unshifting. When you add an element to the end of an array, it can be done instantly. When you unshift and array, you must move the entire array forward, which takes more time with larger arrays of data

Added to JS.

Added sample and random test for JS.

There are no tests for JS. It just says "Should test for something" and '1+1 = 2' which is not the purpose of the kata

your solution is quadratic

Is this quadratic?

i did it in the same way, but i passed all the test

Yes, so you can see with what values your code fails and fix your code.

what do you mean? Like console log the input ?

Too few tests in javascript.

Print the input.

• Please always mention which language you're using when posting a question, issue, or suggestion on a multi-language kata.
• Include enough information so that others can understand and reproduce your problem. In this case: "Expected 0 to equal 6" is far too little information.
• If the tests don't print enough information (which unfortunately many tests on Codementor do), add some print statements to your code.

I'll mark this as resolved. If you still need help, post a new question with more information.