Class FtErr<T, E>

constructor

• new FtErr<T = undefined, E = string>(error: E): FtErr<T, E>

  Creates a failed result with the provided error.

  Type Parameters

  • T = undefined

    The successful value type for the result branch, defaulting to undefined.

  • E = string

    The error type, defaulting to string.

  Parameters

  • error: E

    The error value produced by the failed operation.

  Returns FtErr<T, E>

Readonlyerror

createOuter

• createOuter<OuterT = undefined>(outerError: string): FtErr<OuterT, string>

  Wraps this error in a higher-level error message.

  Type Parameters

  • OuterT = undefined

    The success value type of the wrapped result.

  Parameters

  • outerError: string

    A context label or prefix to prepend to the original error.

  Returns FtErr<OuterT, string>

  A new Err instance whose message is prefixed with outerError.

createOuterResolvedPromise

• createOuterResolvedPromise<OuterT = undefined>(
      outerError: string,
  ): Promise<FtErr<OuterT, string>>

  Wraps this error and resolves it as a promise.

  Type Parameters

  • OuterT = undefined

    The success value type of the wrapped result.

  Parameters

  • outerError: string

    A context label or prefix to prepend to the original error.

  Returns Promise<FtErr<OuterT, string>>

  A promise that resolves to the wrapped error instance.

createType

• createType<NewT>(): FtErr<NewT, E>

  Recreates this error with a different success generic parameter.

  This is useful when an operation fails but the type of a successful value changes in a surrounding call path.

  Type Parameters

  • NewT

    The replacement success value type.

  Returns FtErr<NewT, E>

  A new Err instance preserving the same error payload.

isErr

• isErr(): this is FtErr<T, E>

  Returns true when this instance represents a failed result.

  This method is intended for type narrowing when handling a Result.

  Returns this is FtErr<T, E>

isOk

• isOk(): this is FtOk<T, E>

  Returns true when this instance represents a successful result.

  This is always false for Err.

  Returns this is FtOk<T, E>