Calls fun.(item) and returns item unaltered.

This function mimics the tee program in shell systems, allowing a copy of the passed-in item to be sent to another function amid a pipeline of other functions that are transforming it or handing it off for another value.

Examples

1..10 |> Enum.to_list |> tee(&Logger.info(inspect(&1, label: "`1..10` as a list")))
# (… output from Logger …)
# => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

some_data |> tee(&IO.inspect(&1, label: "encoding as json")) |> Jason.encode!
# => JSON-encoded data