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snippets/js/s/is-async-function.md

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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
+```