byethrow

    Function: andThen()

    Chains the next computation using the success value of a Result or ResultAsync. If the original result is a Failure, it is returned unchanged. Otherwise, the provided function is called, and its result is returned as-is.

    Type Param

    The input Result or ResultAsync.

    Type Param

    The result type returned by fn.

    Examples

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

const 
    const result: Result.Result<number, never>
    result     = 
    import Result
    Result    .
    const pipe: <Result.Result<3, never>, Result.Result<number, never>>(a: Result.Result<3, never>, ab: (a: Result.Result<3, never>) => Result.Result<number, never>) => Result.Result<number, never> (+25 overloads)
    pipe    (    
  
    import Result
    Result    .
    const succeed: <3>(value: 3) => Result.Result<3, never> (+1 overload)
    succeed    (3),    
  
    import Result
    Result    .
    const andThen: <Result.Result<3, never>, Result.Result<number, never>>(fn: (a: 3) => Result.Result<number, never>) => (result: Result.Result<3, never>) => Result.Result<number, never> (+1 overload)
    andThen    ((
    x: 3
    x    ) => 
    import Result
    Result    .
    const succeed: <number>(value: number) => Result.Result<number, never> (+1 overload)
    succeed    (
    x: 3
    x     * 2)),    
);
// { type: 'Success', value: 6 }
    import { 
    import Result
    Result     } from '@praha/byethrow';    

const 
    const result: Result.Result<number, "error">
    result     = 
    import Result
    Result    .
    const pipe: <Result.Result<never, "error">, Result.Result<number, "error">>(a: Result.Result<never, "error">, ab: (a: Result.Result<never, "error">) => Result.Result<number, "error">) => Result.Result<number, "error"> (+25 overloads)
    pipe    (    
  
    import Result
    Result    .
    const fail: <"error">(error: "error") => Result.Result<never, "error"> (+1 overload)
    fail    ('error'),    
  
    import Result
    Result    .
    const andThen: <Result.Result<never, "error">, Result.Result<number, never>>(fn: (a: never) => Result.Result<number, never>) => (result: Result.Result<never, "error">) => Result.Result<number, "error"> (+1 overload)
    andThen    ((
    x: never
    x    ) => 
    import Result
    Result    .
    const succeed: <number>(value: number) => Result.Result<number, never> (+1 overload)
    succeed    (
    x: never
    x     * 2)),    
);
// result: { type: 'Failure', error: 'error' }
    import { 
    import Result
    Result     } from '@praha/byethrow';    

const 
    const result: Result.Result<never, string>
    result     = 
    import Result
    Result    .
    const pipe: <Result.Result<3, never>, Result.Result<never, string>>(a: Result.Result<3, never>, ab: (a: Result.Result<3, never>) => Result.Result<never, string>) => Result.Result<never, string> (+25 overloads)
    pipe    (    
  
    import Result
    Result    .
    const succeed: <3>(value: 3) => Result.Result<3, never> (+1 overload)
    succeed    (3),    
  
    import Result
    Result    .
    const andThen: <Result.Result<3, never>, Result.Result<never, string>>(fn: (a: 3) => Result.Result<never, string>) => (result: Result.Result<3, never>) => Result.Result<never, string> (+1 overload)
    andThen    ((
    x: 3
    x    ) => 
    import Result
    Result    .
    const fail: <string>(error: string) => Result.Result<never, string> (+1 overload)
    fail    ('error: ' + 
    x: 3
    x    )),    
);
// result: { type: 'Failure', error: 'error: 3' }

    See

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

    Call Signature

    andThen<R1, R2>(fn): (result) => ResultFor<R1 | R2, InferSuccess<R2>, InferFailure<R1> | InferFailure<R2>>

    Type Parameters

    R1

    R1 extends ResultMaybeAsync<any, any>

    R2

    R2 extends ResultMaybeAsync<any, any>

    Parameters

    fn

    (a) => R2

    Returns

    (result): ResultFor<R1 | R2, InferSuccess<R2>, InferFailure<R1> | InferFailure<R2>>

    Parameters

    result

    R1

    Returns

    ResultFor<R1 | R2, InferSuccess<R2>, InferFailure<R1> | InferFailure<R2>>

    Call Signature

    andThen<F>(fn): <R1>(result) => ResultFor<R1 | ReturnType<F>, InferSuccess<F>, InferFailure<R1> | InferFailure<F>>

    Type Parameters

    F

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

    Parameters

    fn

    F

    Returns

    <R1>(result): ResultFor<R1 | ReturnType<F>, InferSuccess<F>, InferFailure<R1> | InferFailure<F>>

    Type Parameters

    R1

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

    Parameters

    result

    R1

    Returns

    ResultFor<R1 | ReturnType<F>, InferSuccess<F>, InferFailure<R1> | InferFailure<F>>