Class ResultAsync<T, E>

ResultAsync allows you to work with asynchronous Results in a type safe way

ResultAsync<T,E> is a wrapper around Promise<Result<T,E>> which provides the same methods for chaining different Result and ResultAsync together as Result, while also chaining the asynchronous operations together using Promise.then.

ResultAsync is thenable (implements PromiseLike<T>) so can be used in most places that a Promise can, including with await.

Compatible with neverthrow

Type Parameters

T
The type of the value contained in the ResultAsync for the success case
E
The type of the error contained in the ResultAsync for the failure case

Hierarchy (View Summary)

ResultAsync<T, E>
- ResultAsync

Index

Constructors

constructor

Methods

[asyncIterator] andTee andThen andThrough map mapErr match orElse orTee safeUnwrap then unwrapOr combine combineWithAllErrors fromPromise fromSafePromise fromThrowable

Constructors

constructor

new ResultAsync<T, E>(res: Promise<Result<T, E>>): ResultAsync<T, E>
Type Parameters
- T
 The type of the value contained in the ResultAsync for the success case
- E
 The type of the error contained in the ResultAsync for the failure case
Parameters
- res: Promise<Result<T, E>>
Returns ResultAsync<T, E>
Inherited from neverthrow_ResultAsync<T,E>.constructor
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:7

Methods

[asyncIterator]

"[asyncIterator]"(): AsyncGenerator<Err<never, E>, T>
Returns AsyncGenerator<Err<never, E>, T>
Inherited from neverthrow_ResultAsync.[asyncIterator]
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:42

andTee

andTee(f: (t: T) => unknown): ResultAsync<T, E>
Parameters
- f: (t: T) => unknown
Returns ResultAsync<T, E>
Inherited from neverthrow_ResultAsync.andTee
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:17

andThen

andThen<R extends Result<unknown, unknown>>(
f: (t: T) => R,
): ResultAsync<InferOkTypes<R>, E | InferErrTypes<R>>
Type Parameters
- R extends Result<unknown, unknown>
Parameters
- f: (t: T) => R
Returns ResultAsync<InferOkTypes<R>, E | InferErrTypes<R>>
Inherited from neverthrow_ResultAsync.andThen
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:20
andThen<R extends ResultAsync<unknown, unknown>>(
f: (t: T) => R,
): ResultAsync<InferAsyncOkTypes<R>, E | InferAsyncErrTypes<R>>
Type Parameters
- R extends ResultAsync<unknown, unknown>
Parameters
- f: (t: T) => R
Returns ResultAsync<InferAsyncOkTypes<R>, E | InferAsyncErrTypes<R>>
Inherited from neverthrow_ResultAsync.andThen
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:21
andThen<U, F>(
f: (t: T) => Result<U, F> | ResultAsync<U, F>,
): ResultAsync<U, E | F>
Type Parameters
- U
- F
Parameters
- f: (t: T) => Result<U, F> | ResultAsync<U, F>
Returns ResultAsync<U, E | F>
Inherited from neverthrow_ResultAsync.andThen
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:22

andThrough

andThrough<F>(
f: (t: T) => Result<unknown, F> | ResultAsync<unknown, F>,
): ResultAsync<T, E | F>
Type Parameters
- F
Parameters
- f: (t: T) => Result<unknown, F> | ResultAsync<unknown, F>
Returns ResultAsync<T, E | F>
Inherited from neverthrow_ResultAsync.andThrough
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:16

map

map<A>(f: (t: T) => A | Promise<A>): ResultAsync<A, E>
Type Parameters
- A
Parameters
- f: (t: T) => A | Promise<A>
Returns ResultAsync<A, E>
Inherited from neverthrow_ResultAsync.map
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:15

mapErr

mapErr(f: (e: E) => U | Promise): ResultAsync<T, U>
Type Parameters
- U
Parameters
- f: (e: E) => U | Promise
Returns ResultAsync<T, U>
Inherited from neverthrow_ResultAsync.mapErr
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:19

match

match<A, B = A>(ok: (t: T) => A, _err: (e: E) => B): Promise<A | B>
Type Parameters
- A
- B = A
Parameters
- ok: (t: T) => A
- _err: (e: E) => B
Returns Promise<A | B>
Inherited from neverthrow_ResultAsync.match
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:26

orElse

orElse<R extends Result<unknown, unknown>>(
f: (e: E) => R,
): ResultAsync<T | InferOkTypes<R>, InferErrTypes<R>>
Type Parameters
- R extends Result<unknown, unknown>
Parameters
- f: (e: E) => R
Returns ResultAsync<T | InferOkTypes<R>, InferErrTypes<R>>
Inherited from neverthrow_ResultAsync.orElse
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:23
orElse<R extends ResultAsync<unknown, unknown>>(
f: (e: E) => R,
): ResultAsync<T | InferAsyncOkTypes<R>, InferAsyncErrTypes<R>>
Type Parameters
- R extends ResultAsync<unknown, unknown>
Parameters
- f: (e: E) => R
Returns ResultAsync<T | InferAsyncOkTypes<R>, InferAsyncErrTypes<R>>
Inherited from neverthrow_ResultAsync.orElse
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:24
orElse<U, A>(
f: (e: E) => Result<U, A> | ResultAsync<U, A>,
): ResultAsync<T | U, A>
Type Parameters
- U
- A
Parameters
- f: (e: E) => Result<U, A> | ResultAsync<U, A>
Returns ResultAsync<T | U, A>
Inherited from neverthrow_ResultAsync.orElse
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:25

orTee

orTee(f: (t: E) => unknown): ResultAsync<T, E>
Parameters
- f: (t: E) => unknown
Returns ResultAsync<T, E>
Inherited from neverthrow_ResultAsync.orTee
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:18

safeUnwrap

safeUnwrap(): AsyncGenerator<Err<never, E>, T>
Returns AsyncGenerator<Err<never, E>, T>
Deprecated
will be removed in 9.0.0.

You can use safeTry without this method.
Example
```
safeTry(async function* () {
 const okValue = yield* yourResult
})
```
Emulates Rust's ? operator in safeTry's body. See also safeTry.
Inherited from neverthrow_ResultAsync.safeUnwrap
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:40

then

then<A, B>(
successCallback?: (res: Result<T, E>) => A | PromiseLike<A>,
failureCallback?: (reason: unknown) => B | PromiseLike,
): PromiseLike<A | B>
Attaches callbacks for the resolution and/or rejection of the Promise.
Type Parameters
- A
- B
Parameters
- OptionalsuccessCallback: (res: Result<T, E>) => A | PromiseLike<A>
- OptionalfailureCallback: (reason: unknown) => B | PromiseLike
Returns PromiseLike<A | B>
A Promise for the completion of which ever callback is executed.
Inherited from neverthrow_ResultAsync.then
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:41

unwrapOr

unwrapOr<A>(t: A): Promise<T | A>
Type Parameters
- A
Parameters
- t: A
Returns Promise<T | A>
Inherited from neverthrow_ResultAsync.unwrapOr
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:27

`Static`combine

combine<
 T extends
 readonly [ResultAsync<unknown, unknown>, ResultAsync<unknown, unknown>],
>(
 asyncResultList: T,
): CombineResultAsyncs<T>
Type Parameters
- T extends readonly [ResultAsync<unknown, unknown>, ResultAsync<unknown, unknown>]
Parameters
- asyncResultList: T
Returns CombineResultAsyncs<T>
Inherited from neverthrow_ResultAsync.combine
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:11
combine<T extends readonly ResultAsync<unknown, unknown>[]>(
asyncResultList: T,
): CombineResultAsyncs<T>
Type Parameters
- T extends readonly ResultAsync<unknown, unknown>[]
Parameters
- asyncResultList: T
Returns CombineResultAsyncs<T>
Inherited from neverthrow_ResultAsync.combine
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:12

`Static`combineWithAllErrors

combineWithAllErrors<
 T extends
 readonly [ResultAsync<unknown, unknown>, ResultAsync<unknown, unknown>],
>(
 asyncResultList: T,
): CombineResultsWithAllErrorsArrayAsync<T>
Type Parameters
- T extends readonly [ResultAsync<unknown, unknown>, ResultAsync<unknown, unknown>]
Parameters
- asyncResultList: T
Returns CombineResultsWithAllErrorsArrayAsync<T>
Inherited from neverthrow_ResultAsync.combineWithAllErrors
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:13
combineWithAllErrors<T extends readonly ResultAsync<unknown, unknown>[]>(
asyncResultList: T,
): CombineResultsWithAllErrorsArrayAsync<T>
Type Parameters
- T extends readonly ResultAsync<unknown, unknown>[]
Parameters
- asyncResultList: T
Returns CombineResultsWithAllErrorsArrayAsync<T>
Inherited from neverthrow_ResultAsync.combineWithAllErrors
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:14

`Static`fromPromise

fromPromise<T, E>(
promise: PromiseLike<T>,
errorFn: (e: unknown) => E,
): ResultAsync<T, E>
Type Parameters
- T
- E
Parameters
- promise: PromiseLike<T>
- errorFn: (e: unknown) => E
Returns ResultAsync<T, E>
Inherited from neverthrow_ResultAsync.fromPromise
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:9

`Static`fromSafePromise

fromSafePromise<T, E = never>(promise: PromiseLike<T>): ResultAsync<T, E>
Type Parameters
- T
- E = never
Parameters
- promise: PromiseLike<T>
Returns ResultAsync<T, E>
Inherited from neverthrow_ResultAsync.fromSafePromise
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:8

`Static`fromThrowable

fromThrowable<A extends readonly any[], R, E>(
fn: (...args: A) => Promise<R>,
errorFn?: (err: unknown) => E,
): (...args: A) => ResultAsync<R, E>
Type Parameters
- A extends readonly any[]
- R
- E
Parameters
- fn: (...args: A) => Promise<R>
- OptionalerrorFn: (err: unknown) => E
Returns (...args: A) => ResultAsync<R, E>
Inherited from neverthrow_ResultAsync.fromThrowable
- Defined in node_modules/.pnpm/neverthrow@8.2.0/node_modules/neverthrow/dist/index.d.ts:10

Class ResultAsync<T, E>

Type Parameters

Hierarchy (View Summary)

Index

Constructors

Methods

Constructors

constructor

Type Parameters

Parameters

Returns ResultAsync<T, E>

Methods

[asyncIterator]

Returns AsyncGenerator<Err<never, E>, T>

andTee

Parameters

Returns ResultAsync<T, E>

andThen

Type Parameters

Parameters

Returns ResultAsync<InferOkTypes<R>, E | InferErrTypes<R>>

Type Parameters

Parameters

Returns ResultAsync<InferAsyncOkTypes<R>, E | InferAsyncErrTypes<R>>

Type Parameters

Parameters

Returns ResultAsync<U, E | F>

andThrough

Type Parameters

Parameters

Returns ResultAsync<T, E | F>

map

Type Parameters

Parameters

Returns ResultAsync<A, E>

mapErr

Type Parameters

Parameters

Returns ResultAsync<T, U>

match

Type Parameters

Parameters

Returns Promise<A | B>

orElse

Type Parameters

Parameters

Returns ResultAsync<T | InferOkTypes<R>, InferErrTypes<R>>

Type Parameters

Parameters

Returns ResultAsync<T | InferAsyncOkTypes<R>, InferAsyncErrTypes<R>>

Type Parameters

Parameters

Returns ResultAsync<T | U, A>

orTee

Parameters

Returns ResultAsync<T, E>

safeUnwrap

Returns AsyncGenerator<Err<never, E>, T>

Deprecated

Example

then

Type Parameters

Parameters

Returns PromiseLike<A | B>

unwrapOr

Type Parameters

Parameters

Returns Promise<T | A>

Staticcombine

Type Parameters

Parameters

Returns CombineResultAsyncs<T>

Type Parameters

Parameters

Returns CombineResultAsyncs<T>

StaticcombineWithAllErrors

Type Parameters

Parameters

Returns CombineResultsWithAllErrorsArrayAsync<T>

Type Parameters

`Static`combine

`Static`combineWithAllErrors

`Static`fromPromise

`Static`fromSafePromise

`Static`fromThrowable