# Three built-in iterators in JavaScript

In fact, each iterable object contains not one iterator, but three: `values`, `keys`, and `entries`. Each object type has its own iterator by default. For arrays, this is `values`, and, for example, for a `Map` collection, this is `entries`.

With this knowledge, we can now apply this principle to any collection. For example, let's say we have a `Map` collection:

`let map = new Map(); map.set('a', 1); map.set('b', 2); map.set('c', 3);`

The default iterator for this collection is `entries`:

`for (let elem of map) { console.log(elem); // ['a', 1], ['b', 2], ['c', 3] }`

But we can easily get the keys of our collection:

`for (let elem of map.keys()) { console.log(elem); // 'a', 'b', 'c' }`

We can also get values:

`for (let elem of map.values()) { console.log(elem); // 1, 2, 3 }`

What is the default iterator for a Set collection?

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