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Episode 18: Function Composition Dec 15, 2016

The >> and << functions in Elm allow you to combine two functions to produce a new function. The resulting function is most often useful when passed as a parameter to functions like map and filter.. The direction of the arrow implies how the result is passed along between the functions.

Examples url Http.emptyBody decoder
    |> Http.toTask
    |> (.status >> String.toUpper)
    |> Task.mapError (RemotelyStoreError << httpErrorToString)