Result Namespace

Signature

export declare namespace Result

Interfaces

Interface	Description
Error	Wraps an error of type TError.
Ok	Wraps a result of type TOk.

Enumerations

Enum	Description
ResultType	Tag value use to differentiate the members of the Result discriminated union.

Functions

Function	Return Type	Description
error(error)	Error<TError>	Factory function for making a unsuccessful Result.
isError(result)	result is Error<TError>	Type guard for unsuccessful Result.
isOk(result)	result is Ok<TOk>	Type guard for successful Result.
mapError(result, map)	Result<TOk, TErrorOut>	Maps the given result with the given function when the result is an error.
mapOk(result, map)	Result<TOkOut, TError>	Maps the given result with the given function when the result is ok.
ok(result)	Ok<TOk>	Factory function for making a successful Result.

Function Details

error

Factory function for making a unsuccessful Result.

Signature

function error<TError>(error: TError): Error<TError>;

Type Parameters

Parameter	Description
TError

Parameters

Parameter	Type	Description
error	TError	The error to wrap in the Result.

Returns

Return type: Error<TError>

isError

Type guard for unsuccessful Result.

Signature

function isError<TOk, TError>(result: Result<TOk, TError>): result is Error<TError>;

Type Parameters

Parameter	Description
TOk
TError

Parameters

Parameter	Type	Description
result	Result<TOk, TError>

Returns

True if result is unsuccessful.

Return type: result is Error<TError>

isOk

Type guard for successful Result.

Signature

function isOk<TOk, TError>(result: Result<TOk, TError>): result is Ok<TOk>;

Type Parameters

Parameter	Description
TOk
TError

Parameters

Parameter	Type	Description
result	Result<TOk, TError>

Returns

True if result is successful.

Return type: result is Ok<TOk>

mapError

Maps the given result with the given function when the result is an error.

Signature

function mapError<TOk, TErrorIn, TErrorOut>(result: Result<TOk, TErrorIn>, map: (error: TErrorIn) => TErrorOut): Result<TOk, TErrorOut>;

Type Parameters

Parameter	Description
TOk
TErrorIn
TErrorOut

Parameters

Parameter	Type	Description
result	Result<TOk, TErrorIn>	The result to map.
map	(error: TErrorIn) => TErrorOut	The function to apply to derive the new error.

Returns

The given result if it is ok, the mapped result otherwise.

Return type: Result<TOk, TErrorOut>

mapOk

Maps the given result with the given function when the result is ok.

Signature

function mapOk<TOkIn, TOkOut, TError>(result: Result<TOkIn, TError>, map: (ok: TOkIn) => TOkOut): Result<TOkOut, TError>;

Type Parameters

Parameter	Description
TOkIn
TOkOut
TError

Parameters

Parameter	Type	Description
result	Result<TOkIn, TError>	The result to map.
map	(ok: TOkIn) => TOkOut	The function to apply to derive the new result.

Returns

The given result if it is not ok, the mapped result otherwise.

Return type: Result<TOkOut, TError>

ok

Factory function for making a successful Result.

Signature

function ok<TOk>(result: TOk): Ok<TOk>;

Type Parameters

Parameter	Description
TOk

Parameters

Parameter	Type	Description
result	TOk	The result to wrap in the Result.

Returns

Return type: Ok<TOk>