code: function firstIndex(arr, cb, thisArg) {
    cb = makeIterator(cb, thisArg);
    if (arr == null) {
      return -1;
    }
    var len = arr.length;
    for (var i = 0; i < len; i++) {
      if (cb(arr[i], i, arr)) {
        return i;
      }
    }
    return -1;
  }
docs: Return the first index of the given `type`, or `-1` if not found.
  
  ```js
  utils.firstIndex(['a', 1, 'b', 2, {c: 'd'}, 'c'], 'object');
  //=> 4
  ```
  
  @param  {Array} `array`
  @param  {String} `type` Native type, e.g. `string`, `object`
  @return {Boolean}
  @api public