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30-seconds-of-code/snippets/js/s/is-async-function.md
2023-05-07 16:07:29 +03:00

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---
title: Value is async function
type: snippet
language: javascript
tags: [type,function]
author: chalarangelo
cover: interior-12
dateModified: 2020-10-20T11:21:07+03:00
---
Checks if the given argument is an `async` function.
- Use `Object.prototype.toString()` and `Function.prototype.call()` and check if the result is `'[object AsyncFunction]'`.
```js
const isAsyncFunction = val =>
Object.prototype.toString.call(val) === '[object AsyncFunction]';
```
```js
isAsyncFunction(function() {}); // false
isAsyncFunction(async function() {}); // true
```