26 lines
674 B
Markdown
26 lines
674 B
Markdown
---
|
|
title: isPromiseLike
|
|
tags: type,function,promise,intermediate
|
|
---
|
|
|
|
Returns `true` if an object looks like a [`Promise`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise), `false` otherwise.
|
|
|
|
- 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
|
|
```
|