IsPromise

Since 1.3.0

Check if a type is a Promise. Returns true if the type is a Promise, otherwise false.

Signature

type IsPromise<T> = T extends Promise<any> ? true : false

Parameters

Parameter	Description
T	The type to check

Examples

Basic Usage

import type { IsPromise } from 'uni-types'

type Check1 = IsPromise<Promise<string>> // true
type Check2 = IsPromise<string> // false

With Generic Types

import type { IsPromise } from 'uni-types'

type MaybePromise<T> = IsPromise<T> extends true ? T : Promise<T>

Conditional Logic

import type { IsPromise } from 'uni-types'

type UnwrapIfPromise<T> = IsPromise<T> extends true ? PromiseResult<T> : T

Related

• PromiseResult - Get resolved value from Promise
• WrapPromise - Wrap type in Promise