is-promise-like

Identifies a Promise or an object with a Promise-like interface

Usage no npm install needed!

<script type="module">
  import isPromiseLike from 'https://cdn.skypack.dev/is-promise-like';
</script>

README

IsPromiseLike

Usage with JS

const {
  isPromise,
  isPromiseLike
} = require('is-promise-like')

Usage with ES

import {
  isPromise,
  isPromiseLike
} from 'is-promise-like'

isPromise identifies instances of the global Promise class.

isPromiseLike identifies instances of the global Promise class or other objects which are like them.

Examples: isPromise

Returns true:

const p = new Promise(() => {})

isPromise(p) // true

const p = Promise.resolve({})

isPromise(p) // true

const p = Promise.all([])

isPromise(p) // true

Anything else should return false.

Examples: isPromiseLike

All of the preceding examples returning true. In addition:

class S { 
  static then () {}
} 

isPromiseLike(S) // true

class S { 
  then () {}
} 

const s = new S()

isPromiseLike(s) // true

const o = {}
o.then = () => {}

isPromiseLike(o) // true

const a = []
a.then = () => {}

isPromiseLike(a) // true

And similar constructions for other types. Anything else should return false.