FsToolkit.ErrorHandling
  • README
  • FsToolkit.ErrorHandling
    • Result
      • apply
      • bind
      • check
      • Computation Expression
      • either Functions
      • fold
      • ignore
      • map
      • map2
      • map3
      • mapError
      • Operators
      • orElse Functions
      • Other Functions
      • require Functions
      • tee Functions
      • tryCreate
      • zip
      • zipError
      • Lists
        • traverseResultM
        • sequenceResultM
        • traverseResultA
        • sequenceResultA
      • Sequences
        • traverseResultM
        • sequenceResultM
        • traverseResultA
        • sequenceResultA
      • Transforms
        • ofChoice
    • Option
      • bind
      • bindNull
      • Computation Expression
      • either
      • map
      • map2
      • map3
      • sequenceAsync
      • sequenceResult
      • sequenceTask
      • sequenceTaskResult
      • tee Functions
      • traverseAsync
      • traverseResult
      • traverseTask
      • traverseTaskResult
      • zip
      • Lists
        • traverseOptionM
        • sequenceOptionM
        • traverseVOptionM
        • sequenceVOptionM
      • Sequences
        • traverseOptionM
        • sequenceOptionM
        • traverseVOptionM
        • sequenceVOptionM
      • Transforms
        • ofNull
        • ofPair
        • ofResult
        • ofValueOption
        • toValueOption
    • ResultOption
      • apply
      • bind
      • Computation Expression
      • ignore
      • map
      • map2
      • map3
      • mapError
      • Operators
      • zip
      • zipError
      • Transforms
        • ofChoice
        • ofOption
        • ofResult
    • AsyncResult
      • apply
      • bind
      • check
      • Computation Expression
      • error
      • foldResult
      • ignore
      • map
      • map2
      • map3
      • mapError
      • Operators
      • Other Functions
      • zip
      • zipError
      • List
        • traverseAsyncResultM
        • sequenceAsyncResultM
        • traverseAsyncResultA
        • sequenceAsyncResultA
      • Sequences
        • traverseAsyncResultM
        • sequenceAsyncResultM
        • traverseAsyncResultA
        • sequenceAsyncResultA
      • Transforms
        • ofAsync
        • ofResult
        • ofTask
        • ofTaskAction
    • AsyncOption
      • apply
      • bind
      • Computation Expression
      • either
      • map
      • orElse Functions
      • Other Functions
    • AsyncResultOption
      • apply
      • bind
      • Computation Expression
      • error
      • ignore
      • map
      • map2
      • map3
      • Operators
      • Transforms
        • ofAsyncOption
        • ofAsyncResult
        • ofOption
        • ofResult
    • Task
      • apply
      • bind
      • bindV
      • catch
      • Computation Expression
      • ignore
      • map
      • mapV
      • map2
      • map3
      • zip
      • Transforms
        • ofUnit
    • TaskOption
      • apply
      • bind
      • Computation Expression
      • either
      • map
      • Other Functions
      • zip
    • TaskValueOption
      • apply
      • bind
      • Computation Expression
      • either
      • map
      • Other Functions
      • zip
    • TaskResult
      • apply
      • bind
      • check
      • catch
      • Computation Expression
      • ignore
      • map
      • map2
      • map3
      • mapError
      • Operators
      • Other Functions
      • error
      • zip
      • zipError
      • Lists
        • traverseTaskResultM
        • sequenceTaskResultM
        • traverseTaskResultA
        • sequenceTaskResultA
      • Transforms
        • ofAsync
        • ofResult
        • ofTask
    • TaskResultOption
      • apply
      • bind
      • Computation Expression
      • error
      • ignore
      • map
      • map2
      • map3
      • Operators
    • Validation
      • apply
      • Computation Expression
      • error
      • map
      • map2
      • map3
      • mapError
      • mapErrors
      • Operators
      • zip
      • Transforms
        • ofChoice
        • ofResult
    • AsyncValidation
      • apply
      • Computation Expression
      • error
      • map
      • map2
      • map3
      • mapError
      • mapErrors
      • Operators
      • zip
      • Transforms
        • ofChoice
        • ofResult
    • TaskValidation
      • apply
      • Computation Expression
      • error
      • map
      • map2
      • map3
      • mapError
      • mapErrors
      • Operators
      • zip
      • Transforms
        • ofChoice
        • ofResult
  • FsToolkit.ErrorHandling.AsyncSeq
    • AsyncSeq
      • Computation Expression
  • FsToolkit.ErrorHandling.IcedTasks
    • CancellableTaskOption
      • apply
      • bind
      • Computation Expression
      • either
      • map
      • Other Functions
      • zip
    • CancellableTaskResult
      • apply
      • bind
      • Computation Expression
      • getCancellationToken
      • map
      • Operators
      • Other Functions
      • zip
      • parallelZip
    • CancellableTaskValidation
      • apply
      • bind
      • Computation Expression
      • error
      • getCancellationToken
      • map
      • map2
      • map3
      • mapError
      • mapErrors
      • Operators
      • zip
      • parallelZip
      • Transforms
        • ofChoice
        • ofResult
  • FsToolkit.ErrorHandling.JobResult
    • Job
      • apply
      • map2
      • map3
      • singleton
      • zip
    • JobOption
      • apply
      • bind
      • ce
      • either
      • map
    • JobResult
      • apply
      • bind
      • catch
      • Computation Expression
      • error
      • fromTask
      • fromUnitTask
      • ignore
      • map
      • map2
      • map3
      • mapError
      • Operators
      • Other Functions
      • zip
      • zipError
      • Lists
        • traverseJobResultM
        • sequenceJobResultM
        • traverseJobResultA
        • sequenceJobResultA
      • Transforms
        • ofAsync
        • ofJob
        • ofResult
        • fromTask
        • fromUnitTask
    • JobResultOption
      • apply
      • bind
      • Computation Expression
      • ignore
      • map
      • map2
      • map3
  • General Docs
    • Bind Mappings
Powered by GitBook
On this page
  • Option.traverseTask
  • Examples
  1. FsToolkit.ErrorHandling
  2. Option

traverseTask

PrevioustraverseResultNexttraverseTaskResult

Last updated 1 month ago

Option.traverseTask

Namespace: FsToolkit.ErrorHandling

Function Signature:

('a -> Task<'b>) -> 'a option -> Task<'b option>

Note that traverse is the same as map >> sequence. See also .

See also Scott Wlaschin's .

Examples

Example 1

Let's assume we have a type Customer:

type Customer = {
  Id : int
  Email : string
}

And we have a function called getCustomerByEmail that retrieves a Customer by email address asynchronously from some external source -- a database, a web service, etc:

// string -> Task<Customer>
let getCustomerByEmail email : Task<Customer> = task {
    return { Id = 1; Email = "test@test.com" } // return a constant for simplicity
}

If we have a value of type string option and want to call the getCustomerByEmail function, we can achieve it using the traverseTask function as below:

Some "test@test.com" |> Option.traverseTask getCustomerByEmail
// task { return Some { Id = 1; Email = "test@test.com" } }

None |> Option.traverseTask getCustomerByEmail
// task { return None }
Option.sequenceTask
Understanding traverse and sequence