byethrow
  • 日本語

      • Function: orElse()

      Chains the next computation using the error value of a Result or ResultAsync. If the original result is a Success, 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<0 | 42, never>
      result       = 
      import Result
      Result      .
      const pipe: <Result.Result<42, never>, Result.Result<0 | 42, never>>(a: Result.Result<42, never>, ab: (a: Result.Result<42, never>) => Result.Result<0 | 42, never>) => Result.Result<0 | 42, never> (+25 overloads)
      pipe      (      
  
      import Result
      Result      .
      const succeed: <42>(value: 42) => Result.Result<42, never> (+1 overload)
      succeed      (42),      
  
      import Result
      Result      .
      const orElse: <Result.Result<42, never>, Result.Result<0, never>>(fn: (a: never) => Result.Result<0, never>) => (result: Result.Result<42, never>) => Result.Result<0 | 42, never> (+1 overload)
      orElse      ((
      error: never
      error      ) => 
      import Result
      Result      .
      const succeed: <0>(value: 0) => Result.Result<0, never> (+1 overload)
      succeed      (0)),      
);
// { type: 'Success', value: 42 }
      import { 
      import Result
      Result       } from '@praha/byethrow';      

const 
      const result: Result.Result<"default value", never>
      result       = 
      import Result
      Result      .
      const pipe: <Result.Result<never, "original error">, Result.Result<"default value", never>>(a: Result.Result<never, "original error">, ab: (a: Result.Result<never, "original error">) => Result.Result<"default value", never>) => Result.Result<"default value", never> (+25 overloads)
      pipe      (      
  
      import Result
      Result      .
      const fail: <"original error">(error: "original error") => Result.Result<never, "original error"> (+1 overload)
      fail      ('original error'),      
  
      import Result
      Result      .
      const orElse: <Result.Result<never, "original error">, Result.Result<"default value", never>>(fn: (a: "original error") => Result.Result<"default value", never>) => (result: Result.Result<never, "original error">) => Result.Result<"default value", never> (+1 overload)
      orElse      ((
      error: "original error"
      error      ) => 
      import Result
      Result      .
      const succeed: <"default value">(value: "default value") => Result.Result<"default value", never> (+1 overload)
      succeed      ('default value')),      
);
// result: { type: 'Success', value: 'default value' }
      import { 
      import Result
      Result       } from '@praha/byethrow';      

const 
      const result: Result.Result<never, string>
      result       = 
      import Result
      Result      .
      const pipe: <Result.Result<never, "original error">, Result.Result<never, string>>(a: Result.Result<never, "original error">, ab: (a: Result.Result<never, "original error">) => Result.Result<never, string>) => Result.Result<never, string> (+25 overloads)
      pipe      (      
  
      import Result
      Result      .
      const fail: <"original error">(error: "original error") => Result.Result<never, "original error"> (+1 overload)
      fail      ('original error'),      
  
      import Result
      Result      .
      const orElse: <Result.Result<never, "original error">, Result.Result<never, string>>(fn: (a: "original error") => Result.Result<never, string>) => (result: Result.Result<never, "original error">) => Result.Result<never, string> (+1 overload)
      orElse      ((
      error: "original error"
      error      ) => 
      import Result
      Result      .
      const fail: <string>(error: string) => Result.Result<never, string> (+1 overload)
      fail      ('new error: ' + 
      error: "original error"
      error      )),      
);
// result: { type: 'Failure', error: 'new error: original error' }

      See

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

      Call Signature

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

      Parameters

      result

      R1

      Returns

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

      Call Signature

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

      Type Parameters

      F

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

      Parameters

      fn

      F

      Returns

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

      Type Parameters

      R1

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

      Parameters

      result

      R1

      Returns

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