Why can't direcrlty return a value by using .push() in javascript?

Question

using below flatten function as example, why cant I use return directly on the accumulator. Push()

 function flatten(array){
      return reduce(arr         


        

Answer 1

The push method returns the new length of the Array.

MDN documentation for push

The concat method returns a brand new array containing a combination of the two arrays.

MDN documentation for concat