code: function indexOf(array, value, fromIndex) {
      var length = array ? array.length : 0;
      if (typeof fromIndex == 'number') {
        fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : fromIndex;
      } else {
        fromIndex = 0;
      }
      var index = (fromIndex || 0) - 1,
          isReflexive = value === value;
  
      while (++index < length) {
        var other = array[index];
        if ((isReflexive ? other === value : other !== other)) {
          return index;
        }
      }
      return -1;
    }
docs: Gets the index at which the first occurrence of `value` is found in `array`
  using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
  for equality comparisons. If `fromIndex` is negative, it's used as the
  offset from the end of `array`.
  
  @static
  @memberOf _
  @since 0.1.0
  @category Array
  @param {Array} array The array to search.
  @param {*} value The value to search for.
  @param {number} [fromIndex=0] The index to search from.
  @returns {number} Returns the index of the matched value, else `-1`.
  @example
  
  _.indexOf([1, 2, 1, 2], 2);
  // => 1
  
  // Search from the `fromIndex`.
  _.indexOf([1, 2, 1, 2], 2, 2);
  // => 3