1  var baseFindIndex = require('./_baseFindIndex'),
 2      baseIteratee = require('./_baseIteratee'),
 3      toInteger = require('./toInteger');
 4  
 5  /* Built-in method references for those with the same name as other `lodash` methods. */
 6  var nativeMax = Math.max;
 7  
 8  /**
 9   * This method is like `_.find` except that it returns the index of the first
10   * element `predicate` returns truthy for instead of the element itself.
11   *
12   * @static
13   * @memberOf _
14   * @since 1.1.0
15   * @category Array
16   * @param {Array} array The array to inspect.
17   * @param {Function} [predicate=_.identity] The function invoked per iteration.
18   * @param {number} [fromIndex=0] The index to search from.
19   * @returns {number} Returns the index of the found element, else `-1`.
20   * @example
21   *
22   * var users = [
23   *   { 'user': 'barney',  'active': false },
24   *   { 'user': 'fred',    'active': false },
25   *   { 'user': 'pebbles', 'active': true }
26   * ];
27   *
28   * _.findIndex(users, function(o) { return o.user == 'barney'; });
29   * // => 0
30   *
31   * // The `_.matches` iteratee shorthand.
32   * _.findIndex(users, { 'user': 'fred', 'active': false });
33   * // => 1
34   *
35   * // The `_.matchesProperty` iteratee shorthand.
36   * _.findIndex(users, ['active', false]);
37   * // => 0
38   *
39   * // The `_.property` iteratee shorthand.
40   * _.findIndex(users, 'active');
41   * // => 2
42   */
43  function findIndex(array, predicate, fromIndex) {
44    var length = array == null ? 0 : array.length;
45    if (!length) {
46      return -1;
47    }
48    var index = fromIndex == null ? 0 : toInteger(fromIndex);
49    if (index < 0) {
50      index = nativeMax(length + index, 0);
51    }
52    return baseFindIndex(array, baseIteratee(predicate, 3), index);
53  }
54  
55  module.exports = findIndex;