bind
Namespace: FsToolkit.ErrorHandling
Function Signature
('TInput -> Async<'TOutput option>) -> Async<'TInput option> -> Async<'TOutput option>
Examples
Take the following function for example
type Account =
{ EmailAddress : string
Name : string }
// string -> Async<Account option>
let lookupAccountByEmail email = async {
let john = { EmailAddress = "john@test.com"; Name = "John Johnson" }
let jeff = { EmailAddress = "jeff@test.com"; Name = "Jeff Jefferson" }
let jack = { EmailAddress = "jack@test.com"; Name = "Jack Jackson" }
// Just a map lookup, but imagine we look up an account in our database
let accounts = Map.ofList [
("john@test.com", john)
("jeff@test.com", jeff)
("jack@test.com", jack)
]
return Map.tryFind email accounts
}
Example 1
let asyncOpt : Async<Account option> =
AsyncOption.some "john@test.com" // Async<string option>
|> AsyncOption.bind lookupAccountByEmail // Async<Account option>
// async { Some { EmailAddress = "john@test.com"; Name = "John Johnson" } }
Example 2
let asyncOpt : Async<Account option> =
AsyncOption.some "jerry@test.com" // Async<string option>
|> AsyncOption.bind lookupAccountByEmail // Async<Account option>
// async { None }
Example 3
let asyncOpt : Async<Account option> =
Async.singleton None // Async<string option>
|> AsyncOption.bind lookupAccountByEmail // Async<Account option>
// async { None }
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