How to check if a value is an async function in JavaScript

In this Article we will go through how to check if a value is an async function only using single line of code in JavaScript. This is a one-line JavaScript code snippet that uses one of the most popular ES6 features => Arrow Function.

Let's define this short function:

const isAsyncFunction = v => Object.prototype.toString.call(v) === '[object AsyncFunction]';

isAsyncFunction(function() {});         // false
isAsyncFunction(function*() {});        // false
isAsyncFunction(async function() {});   // true