17 lines
583 B
Markdown
17 lines
583 B
Markdown
### isPromise
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Returns `true` if an object looks like a [`Promise`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise), `false` otherwise.
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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`.
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```js
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const isPromise = obj =>
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obj !== null && (typeof obj === 'object' || typeof obj === 'function') && typeof obj.then === 'function';
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```
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```js
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isPromise({then:function () {return ''}}); // true
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isPromise(null); // false
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isPromise({}); // false
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```
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