byethrow
  • English

      • Type Alias: ResultFor<R, T, E>

      ResultFor<R, T, E> = true extends HasPromise<R> ? ResultAsync<T, E> : Result<T, E>

      Resolves to the appropriate Result type (sync or async) based on the input type.

      Typically used to conditionally infer return types based on whether the original computation was async.

      Type Parameters

      R

      R

      The reference type to inspect for a Promise.

      T

      T

      The type of the Success value.

      E

      E

      The type of the Failure value.

      Examples

      With a Promise-returning function

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

type 
      type R = Promise<Result.Result<number, string>>
      R       = 
      import Result
      Result      .
      type ResultAsync<T, E> = Promise<Result.Result<T, E>>
      An asynchronous variant of
Result
, wrapped in a Promise.
      @typeParamT  - The type of the Success value.@typeParamE  - The type of the Failure value.@example
      import { Result } from '@praha/byethrow';

const fetchData = async (): Result.ResultAsync<string, Error> => {
  try {
    const data = await fetch('...');
    return { type: 'Success', value: await data.text() };
  } catch (err) {
    return { type: 'Failure', error: err as Error };
  }
};
      @categoryCore  Types
      ResultAsync      <number, string>;      
type 
      type Output = Promise<Result.Result<number, string>>
      Output       = 
      import Result
      Result      .
      type ResultFor<R, T, E> = true extends HasPromise<R> ? Result.ResultAsync<T, E> : Result.Result<T, E>
      Resolves to the appropriate Result type (sync or async) based on the input type.
      

      Typically used to conditionally infer return types based on whether the original computation was async.
      @typeParamR  - The reference type to inspect for a Promise.@typeParamT  - The type of the Success value.@typeParamE  - The type of the Failure value.@example
      With  a Promise-returning function
      

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

type R = Result.ResultAsync<number, string>;
type Output = Result.ResultFor<R, number, string>; // Result.ResultAsync<number, string>
      @example
      With  a non-Promise-returning function
      

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

type R = Result.Result<number, string>;
type Output = Result.ResultFor<R, number, string>; // Result.Result<number, string>
      @categoryCore  Types
      ResultFor      <
      type R = Promise<Result.Result<number, string>>
      R      , number, string>; // Result.ResultAsync<number, string>

      With a non-Promise-returning function

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

type 
      type R = Result.Success<number> | Result.Failure<string>
      R       = 
      import Result
      Result      .
      type Result<T, E> = Result.Success<T> | Result.Failure<E>
      A union type representing either a success or a failure.
      @typeParamT  - The type of the Success value.@typeParamE  - The type of the Failure value.@example
      import { Result } from '@praha/byethrow';

const doSomething = (): Result.Result<number, string> => {
  return Math.random() > 0.5
    ? { type: 'Success', value: 10 }
    : { type: 'Failure', error: 'Oops' };
};
      @categoryCore  Types
      Result      <number, string>;      
type 
      type Output = Result.Success<number> | Result.Failure<string>
      Output       = 
      import Result
      Result      .
      type ResultFor<R, T, E> = true extends HasPromise<R> ? Result.ResultAsync<T, E> : Result.Result<T, E>
      Resolves to the appropriate Result type (sync or async) based on the input type.
      

      Typically used to conditionally infer return types based on whether the original computation was async.
      @typeParamR  - The reference type to inspect for a Promise.@typeParamT  - The type of the Success value.@typeParamE  - The type of the Failure value.@example
      With  a Promise-returning function
      

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

type R = Result.ResultAsync<number, string>;
type Output = Result.ResultFor<R, number, string>; // Result.ResultAsync<number, string>
      @example
      With  a non-Promise-returning function
      

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

type R = Result.Result<number, string>;
type Output = Result.ResultFor<R, number, string>; // Result.Result<number, string>
      @categoryCore  Types
      ResultFor      <
      type R = Result.Success<number> | Result.Failure<string>
      R      , number, string>; // Result.Result<number, string>