code: function filter(arr, cb, thisArg) {
    cb = makeIterator(cb, thisArg);
    if (arr == null) {
      return [];
    }
    var len = arr.length;
    var res = [];
    for (var i = 0; i < len; i++) {
      var ele = arr[i];
  
      if (cb(ele, i, arr)) {
        res.push(ele);
      }
    }
    return res;
  }
docs: Like JavaScript's native filter method, but faster.
  
  @param  {Array}  `arr` The array to filter
  @param  {Function} `cb` Callback function.
  @param  {Array} `thisArg`
  @return {Array}