Free Code Camp Bonfire: Steamroller

// Bonfire: Steamroller
// Author: @radumazilu
// Challenge: http://www.freecodecamp.com/challenges/bonfire-steamroller
// Learn to Code at Free Code Camp (www.freecodecamp.com)

function steamroller(arr) {
  // I'm a steamroller, baby
  var newArr = [];
  var check = function(x){
    if(Array.isArray(x) !== true){
      newArr.push(x);
    }else{
      for(var i = 0; i < x.length; i++){
        check(x[i]);
      }
    }
  };
  for(var i = 0; i < arr.length; i++){
    check(arr[i]);
  }
  return newArr;
}

steamroller([[["a"]], [["b"]]]);