# `containsOneItem()` The containsOneItem method returns true if the collection contains exactly one item; otherwise, false is returned: ```js collect([1]).containsOneItem(); // true collect({ firstname: 'Luis' }).containsOneItem(); // true collect('value').containsOneItem(); // true collect([1, 2, 3]).containsOneItem(); // false collect({ firstname: 'Luis', lastname: 'Díaz' }).containsOneItem(); // false collect().containsOneItem(); // false collect([]).containsOneItem(); // false collect({}).containsOneItem(); // false ``` [View source on GitHub](https://github.com/ecrmnn/collect.js/blob/master/src/methods/containsOneItem.js)