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Add setTimeout with zero delay (Solves #270) #271

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26 changes: 26 additions & 0 deletions README.md
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Expand Up @@ -122,6 +122,7 @@ Currently, there are these translations of **wtfjs**:
- [Split a string by a space](#split-a-string-by-a-space)
- [A stringified string](#a-stringified-string)
- [Non-strict comparison of a number to `true`](#non-strict-comparison-of-a-number-to-true)
- [setTimeout with zero delay](#settimeout-with-zero-delay)
- [📚 Other resources](#-other-resources)
- [🤝 Supporting](#-supporting)
- [🎓 License](#-license)
Expand Down Expand Up @@ -2212,6 +2213,31 @@ So this comparison is performed like this:

- [**7.2.15** Abstract Equality Comparison](https://262.ecma-international.org/11.0/index.html#sec-abstract-equality-comparison)

## setTimeout with zero delay
```
setTimeout(() => {
console.log("Foo");
}, 0);

console.log("Bar");
```

The output for the above block of code returns:
```
Bar
Foo
```

### 💡 Explanation:
Although, `setTimeout` is called with `0ms` delay. It still waits for all the lines of code in the document to finish execution before it could print this.

The reason being, setTimeout which is a part of Web APIs maintains its own stack which when popped goes into the callback queue/task queue. JavaScript executes all the lines of a document using the traditional call stack. The callback queue pushes the callback to the call stack only when the call stack is empty (when the entire document has been executed).

**Links:**
- [JSConf EU - What the heck is event loop anyway?](https://www.youtube.com/watch?v=8aGhZQkoFbQ&t=1560s) by Philip Roberts
- [MDN Web Docs for Web APIs](https://developer.mozilla.org/en-US/docs/Web/API)
- [JS Visualizer](https://www.jsv9000.app/)

# 📚 Other resources

- [wtfjs.com](http://wtfjs.com/) — a collection of those very special irregularities, inconsistencies and just plain painfully unintuitive moments for the language of the web.
Expand Down