.findKey(object, [predicate=.identity])

sourcenpm package

This method is like _.find except that it returns the key of the first element predicate returns truthy for instead of the element itself.

Since

1.1.0

Arguments

• object (Object): The object to inspect.
• [predicate=.identity] (Function)_: The function invoked per iteration.

Returns

(*): Returns the key of the matched element, else undefined.

Example

var users = {
  'barney':  { 'age': 36, 'active': true },
  'fred':    { 'age': 40, 'active': false },
  'pebbles': { 'age': 1,  'active': true }
};
 
_.findKey(users, function(o) { return o.age < 40; });
// => 'barney' (iteration order is not guaranteed)
 
// The `_.matches` iteratee shorthand.
_.findKey(users, { 'age': 1, 'active': true });
// => 'pebbles'
 
// The `_.matchesProperty` iteratee shorthand.
_.findKey(users, ['active', false]);
// => 'fred'
 
// The `_.property` iteratee shorthand.
_.findKey(users, 'active');
// => 'barney'