FsToolkit.ErrorHandling
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  • FsToolkit.ErrorHandling
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        • ofChoice
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  • FsToolkit.ErrorHandling.AsyncSeq
    • AsyncSeq
      • Computation Expression
  • FsToolkit.ErrorHandling.IcedTasks
    • CancellableTaskOption
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        • ofChoice
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  • FsToolkit.ErrorHandling.JobResult
    • Job
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  • General Docs
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  • Option.traverseTaskResult
  • Examples
  1. FsToolkit.ErrorHandling
  2. Option

traverseTaskResult

PrevioustraverseTaskNextzip

Last updated 1 month ago

Option.traverseTaskResult

Namespace: FsToolkit.ErrorHandling

Function Signature:

('a -> Task<Result<'b,'c>>) -> 'a option -> Task<Result<'b option, 'c>>

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

See also Scott Wlaschin's .

Examples

Example 1

Say we have a function to get a number from a database (asynchronously), and multiply our input by that number if it's found:

let tryMultiplyWithDatabaseValue: float -> Task<Result<float, string>> = // ...

If we start with an optional value, then we could map this function using Option.traverseTaskResult as follows:

let input = Some 1.234

input // float option
|> Option.traverseTaskResult tryMultiplyWithDatabaseValue // Task<Result<float option, string>>

If we combine this with the , we could directly let! the output:

taskResult {
    let input = Some 1.234

    let! output = // float option
        input // float option
        |> Option.traverseTaskResult tryMultiplyWithDatabaseValue // Task<Result<float option, string>>
}
Option.sequenceTaskResult
Understanding traverse and sequence
TaskResult computation expression