var users = [ { 'user': 'barney', 'active': false }, { 'user': 'fred', 'active': false }, { 'user': 'pebbles', 'active': true } ];
_.findIndex(users, function(o) { return o.user == 'barney'; }); // => 0
// The `_.matches` iteratee shorthand. _.findIndex(users, { 'user': 'fred', 'active': false }); // => 1
// The `_.matchesProperty` iteratee shorthand. _.findIndex(users, ['active', false]); // => 0
// The `_.property` iteratee shorthand. _.findIndex(users, 'active'); // => 2