removeElement.js

function reduce(index) {
  var arr = [1,2,3,4,5];
  return arr.slice(0, index).concat(arr.slice(index + 1)); 
}

//Passing your own array

function reduce(iarr, index) {
  var arr = iarr;
  return arr.slice(0, iarr.length - index).concat(arr.slice(index + 1)); 
}