orElseFunctions.md

OrElse Functions

AsyncOption.orElse

Namespace: FsToolkit.ErrorHandling

Returns the option if the option is Some, otherwise returns the given option

Function Signature

(ifNone : Async<'value option>) -> (input : Async<'value option>) 
    -> Async<'value option>

Examples

Example 1

let asyncOption : Async<int option> =
    AsyncOption.some 1
    |> AsyncOption.orElse (AsyncOption.some 2)
    
// async { Some 1 }

Example 2

let asyncOption : Async<int option> =
    AsyncOption.some 1
    |> AsyncOption.orElse (Async.singleton None)
    
// async { Some 1 }

Example 3

let asyncOption : Async<int option> =
    Async.singleton None
    |> AsyncOption.orElse (Some 2)
    
// async { Some 2 }

Example 4

let asyncOption : Async<int option> =
    Async.singleton None
    |> AsyncOption.orElse (Async.singleton None)

// async { None }

AsyncOption.orElseWith

Namespace: FsToolkit.ErrorHandling

Returns the option if the option is Some, otherwise evaluates the given function and returns the result.

Function Signature

(ifNoneFunc : unit -> Async<'value option>) -> (input : Async<'value option>)
    -> Async<'value option>

Examples

Example 1

let asyncOption : Async<int option> =
    AsyncOption.some 1
    |> AsyncOption.orElseWith (fun () -> AsyncOption.some 2)

// async { Some 1 }

Example 2

let asyncOption : Async<int option> =
    AsyncOption.some 1
    |> AsyncOption.orElseWith (fun () -> None)

// async { Some 1 }

Example 3

let asyncOption : Async<int option> =
    Async.singleton None
    |> AsyncOption.orElseWith (fun () -> AsyncOption.some 2)

// async { Some 2 }

Example 4

let asyncOption : Async<int option> =
    Async.singleton None
    |> AsyncOption.orElseWith (fun () -> Async.singleton None)

// async { None }