#Type Alias: ResultFor<R, T, E>
ResultFor<
R,T,E> =trueextendsHasPromise<R> ?ResultAsync<T,E> :Result<T,E>
Defined in: result.ts:145
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
import { import Resulttype R = Promise<Result.Result<number, string>>import Resulttype 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.@exampleimport { 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 };
}
};
Core Typestype Output = Promise<Result.Result<number, string>>import Resulttype 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.@exampleWith 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>
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>
Core Typestype R = Promise<Result.Result<number, string>>import { import Resulttype R = Result.Success<number> | Result.Failure<string>import Resulttype 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.@exampleimport { Result } from '@praha/byethrow';
const doSomething = (): Result.Result<number, string> => {
return Math.random() > 0.5
? { type: 'Success', value: 10 }
: { type: 'Failure', error: 'Oops' };
};
Core Typestype Output = Result.Success<number> | Result.Failure<string>import Resulttype 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.@exampleWith 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>
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>
Core Typestype R = Result.Success<number> | Result.Failure<string>