lodash反向检索对象的属性和对应的值

varusers= {
'barney':  { 'age': 36, 'active': true },
'fred':    { 'age': 40, 'active': false },
'pebbles': { 'age': 1,  'active': true }
};
_.findLastKey(users, function(o) { returno.age<40; });
// => returns 'pebbles' assuming `_.findKey` returns 'barney'// The `_.matches` iteratee shorthand._.findLastKey(users, { 'age': 36, 'active': true });
// => 'barney'// The `_.matchesProperty` iteratee shorthand._.findLastKey(users, ['active', false]);
// => 'fred'// The `_.property` iteratee shorthand._.findLastKey(users, 'active');
// => 'pebbles'