# setTimeout is not a part of JavaScipt

Maybe you think setTimeout like this -: **The setTimeout() method calls a function or evaluates an expression after a specified number of milliseconds.** it's true, but let's dive deeper.

There aren't any methods like `setTimeout()` or `setInterval()` in JavaScript. They are not provided by the JavaScript engine itself but they are provided by browser as part of the window object. Let's break it down: 

If javascript doesn't provide `setInterval()` and `setTimeout()` but when we run our javascript code which also contains **setTImeout**  it works perfectly fine. Yes, that's the real problem. Many people know how to use and they don't have any idea about what's going on under the hood. Before knowing about windows object, let's look at web APIs.

### Web APIs 
A browser can perform many tasks like getting user's location, turning on/off bluetooth, storage tasks, timer related tasks and many more. And we as a developers need these things. So, all these things can be accessed by JavaScript via Web APIs. That's it, now we have all these things inside one place and that place is window object.

#### Some web APIs:
- localStorage
- setTimeout()
- console
- DOM APIs
- fetch()
- location
- alert()
- and [others](https://developer.chrome.com/docs/apps/api_other/)

If `setTimeout()` is present inside `window` object then why we don't write like this:
```javascript
window.setTimeout(() => console.log('Timer finished'), 1000 );
```

Instead we write without `window` object:
```javascript
setTimeout(() => console.log('Timer finished'), 1000 );
```

`window` is a global object and `setTimeout()` is present inside global object(at global scope), so we can access `setTimeout()` without `window` object. Not only with `setTimeout()`, we don't need to write `window` object to access `alert`, `localstorage`, and other web APIs.

Far by we've discussed that the browser provides web APIs, so we can use the things like`setTimeout()` but nodejs is not a browser. Then how is it possible to access `setTimeout()` in node. Well, we don't have `window` object available while working with node. But we can still access `setTimeout()`, let me tell you something at this point `setTimeout()` function in node works similar to `window.setTimeout()`, however they are not exactly same. Read more about this [here](https://nodejs.org/en/docs/guides/timers-in-node/).