#Function: bind()

Chains another Result-producing computation and merges its success value into the existing object under the specified key.

• If the original result is a Failure, it is returned as-is.
• If the next result is a Failure, it is returned as-is.
• If both are Success, a new object is returned by shallow-merging: the original success object and { [name]: nextSuccess }.

This is useful for building up objects in a compositional and type-safe way, especially in validation or data-fetching pipelines.

#Type Param

The key to assign the result of the fn computation.

#Type Param

The input Result or ResultAsync.

#Type Param

The result type returned by fn.

#Examples

import { Result } from '@praha/byethrow';

const result = Result.pipe(
  Result.succeed({ name: 'Alice' }),
  Result.bind('age', (user) => Result.succeed(20)),
);
// { type: 'Success', value: { name: 1, age: 20 } }

import { Result } from '@praha/byethrow';

const result = Result.pipe(
  Result.fail('error'),
  Result.bind('age', (user) => Result.succeed(20)),
);
// { type: 'Failure', error: 'error' }

import { Result } from '@praha/byethrow';

const result = Result.pipe(
  Result.succeed({ name: 'Alice' }),
  Result.bind('age', (user) => Result.fail('error')),
);
// { type: 'Failure', error: 'error' }

#See

pipe - It is recommended to use this function with the pipe function for better readability and composability.

#Call Signature

bind<N, R1, R2>(name, fn): (result) => InferSuccess<R1> extends object ? ResultFor<R1 | R2, { [K in string | number | symbol]: K extends keyof InferSuccess<InferSuccess<R1>> ? InferSuccess<InferSuccess<R1>>[K<K>] : InferSuccess<R2> }, InferFailure<R1> | InferFailure<R2>> : unknown

Defined in: functions/bind.ts:64

#Type Parameters

#N

N extends string

#R1

R1 extends ResultMaybeAsync<any, any>

#R2

R2 extends ResultMaybeAsync<any, any>

#Parameters

#name

N

#fn

(a) => R2

#Returns

(result): InferSuccess<R1> extends object ? ResultFor<R1 | R2, { [K in string | number | symbol]: K extends keyof InferSuccess<InferSuccess<R1>> ? InferSuccess<InferSuccess<R1>>[K<K>] : InferSuccess<R2> }, InferFailure<R1> | InferFailure<R2>> : unknown

#Parameters

#result

R1

#Returns

InferSuccess<R1> extends object ? ResultFor<R1 | R2, { [K in string | number | symbol]: K extends keyof InferSuccess<InferSuccess<R1>> ? InferSuccess<InferSuccess<R1>>[K<K>] : InferSuccess<R2> }, InferFailure<R1> | InferFailure<R2>> : unknown

#Call Signature

bind<N, F>(name, fn): <R1>(result) => Parameters<F>[0] extends object ? ResultFor<R1 | ReturnType<F>, { [K in string | number | symbol]: K extends keyof any[any] ? any[any][K<K>] : InferSuccess<F> }, InferFailure<R1> | InferFailure<F>> : unknown

Defined in: functions/bind.ts:65

#Type Parameters

#N

N extends string

#F

F extends (a) => ResultMaybeAsync<any, any>

#Parameters

#name

N

#fn

F

#Returns

<R1>(result): Parameters<F>[0] extends object ? ResultFor<R1 | ReturnType<F>, { [K in string | number | symbol]: K extends keyof any[any] ? any[any][K<K>] : InferSuccess<F> }, InferFailure<R1> | InferFailure<F>> : unknown

#Type Parameters

#R1

R1 extends ResultMaybeAsync<Parameters<F>[0], any>

#Parameters

#result

R1

#Returns

Parameters<F>[0] extends object ? ResultFor<R1 | ReturnType<F>, { [K in string | number | symbol]: K extends keyof any[any] ? any[any][K<K>] : InferSuccess<F> }, InferFailure<R1> | InferFailure<F>> : unknown