Result

extension Result

`

                success
                `

Returns the associated value if the result is a success, nil otherwise.

Declaration

Swift

var success: Success? { get }

`

                failure
                `

Returns the associated error value if the result is a failure, nil otherwise.

Declaration

Swift

var failure: Failure? { get }

`

                init(value:error:)
                `

Initializes a Result from value or error. Returns .failure if the error is non-nil, .success otherwise.

Declaration

Swift

init(value: Success, error: Failure?)

Parameters

| value |

A value.

| | error |

An Error.

|

`

                tryMap(_:)
                `

Evaluates the specified closure when the Result is a success, passing the unwrapped value as a parameter.

Use the tryMap method with a closure that may throw an error. For example:

let possibleData: Result<Data, Error> = .success(Data(...))
let possibleObject = possibleData.tryMap {
    try JSONSerialization.jsonObject(with: $0)
}

Declaration

Swift

func tryMap<NewSuccess>(_ transform: (Success) throws -> NewSuccess) -> Result<NewSuccess, Error>

Parameters

| transform |

A closure that takes the success value of the instance.

|

Return Value

A Result containing the result of the given closure. If this instance is a failure, returns the same failure.

`

                tryMapError(_:)
                `

Evaluates the specified closure when the Result is a failure, passing the unwrapped error as a parameter.

Use the tryMapError function with a closure that may throw an error. For example:

let possibleData: Result<Data, Error> = .success(Data(...))
let possibleObject = possibleData.tryMapError {
    try someFailableFunction(taking: $0)
}

Declaration

Swift

func tryMapError<NewFailure>(_ transform: (Failure) throws -> NewFailure) -> Result<Success, Error> where NewFailure : Error

Parameters

| transform |

A throwing closure that takes the error of the instance.

|

Return Value

A Result instance containing the result of the transform. If this instance is a success, returns the same success.