# Delay with a promise

The built-in function `setTimeout` uses callbacks. Create a promise-based alternative.

The function `delay(ms)` should return a promise. That promise should resolve after `ms` milliseconds, so that we can add `.then` to it, like this:

```js
function delay(ms) {
  // your code
}

delay(3000).then(() => alert('runs after 3 seconds'));
```