Async Utilities

Since 1.3.0

Promise and async type utilities.

Promise Value Extraction

PromiseValue

Extract the value type from a Promise (recursively).

import type { PromiseValue } from 'uni-types'

type Value = PromiseValue<Promise<string>>  // string
type Nested = PromiseValue<Promise<Promise<number>>>  // number

PromiseResult

Get the resolved value type from Promise (single level).

import type { PromiseResult } from 'uni-types'

type Result = PromiseResult<Promise<string>>  // string
type Nested = PromiseResult<Promise<Promise<number>>>  // Promise<number>

IsPromise

Check if type is a Promise.

import type { IsPromise } from 'uni-types'

type Is = IsPromise<Promise<string>>  // true
type Not = IsPromise<string>  // false

UnwrapPromise / WrapPromise

Promise wrapping utilities.

import type { UnwrapPromise, WrapPromise } from 'uni-types'

type Value = UnwrapPromise<Promise<string>>  // string
type Wrapped = WrapPromise<string>  // Promise<string>

Promise Settlement Types

PromiseSettledResult

Result of a settled promise.

import type { PromiseSettledResult, PromiseFulfilledResult, PromiseRejectedResult } from 'uni-types'

type Result = PromiseSettledResult<string>
// PromiseFulfilledResult<string> | PromiseRejectedResult

Async Function Types

AsyncReturnTypeFromPromise

Get return type of async function (unwrapped).

import type { AsyncReturnTypeFromPromise } from 'uni-types'

type Value = AsyncReturnTypeFromPromise<() => Promise<string>>  // string

AsyncParameters

Get parameters of async function.

import type { AsyncParameters } from 'uni-types'

type Params = AsyncParameters<(a: string, b: number) => Promise<void>>  // [string, number]

MakeAsync

Make function async.

import type { MakeAsync } from 'uni-types'

type AsyncFn = MakeAsync<(x: string) => number>  // (x: string) => Promise<number>

Async Result Types

AsyncResult

Rust-style async result type.

import type { AsyncResult, AsyncSuccess, AsyncFailure } from 'uni-types'

type Result = AsyncResult<string, Error>
// AsyncSuccess<string> | AsyncFailure<Error>

Related

• Functions - Function type utilities
• Concurrency - Concurrency patterns