# The setTimeout() method in JavaScript

If you want to run something once after a set time use `setTimeout()`

## Set Timeout

`setTimeout()` is a window method available to us. It takes two things:

- A callback function
- Time in milliseconds

```javascript
setTimeout(() => {
  console.log('1 second!');
}, 1000);
// '1 second!'
```

In the example an _anonymous_ function `() =>` is passed in. The time in **milliseconds** is passed at the very end `}, 1000)`. `1 second` is printed to the console **after** 1 second has passed once the rendered.

You can also pass a function into `setTimeout`.

```javascript
const oneSec = () => {
  console.log('1 second');
};
// '1 second'

setTimeout(oneSec, 1000);
```

The function `oneSec()` is ran **after** 1000 milliseconds.

`setTimeout()` is a good way for understanding the `asynchronous` nature of JavaScript. See the example below.

```javascript
const oneSec = () => {
  console.log('1 second');
};

setTimeout(oneSec, 1000);
console.log('Me first!');
// 'Me first!'
// '1 second'
```

In the example `Me first!` is printed to the console. before `1 second` even though the setTimeout is written before the `console.log`. The code will call `oneSec` after 1000 milliseconds but in the mean time it continues to read the rest of the code. This is why it's called a `callback` function.

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