---
title: Value is promise-like
tags: type,function,promise
cover: digital-nomad-13
firstSeen: 2017-12-31T14:25:43+02:00
lastUpdated: 2020-10-20T23:02:01+03:00
---

Checks if an object looks like a [`Promise`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise).

- Check if the object is not `null`, its `typeof` matches either `object` or `function` and if it has a `.then` property, which is also a `function`.

```js
const isPromiseLike = obj =>
  obj !== null &&
  (typeof obj === 'object' || typeof obj === 'function') &&
  typeof obj.then === 'function';
```

```js
isPromiseLike({
  then: function() {
    return '';
  }
}); // true
isPromiseLike(null); // false
isPromiseLike({}); // false
```