Pipeline tap operator `|:`

💡 Ideas
9

Just thought of another way to do it, without even using the tap operator.

const doTransfomration = data => data
  .filter(x => x != null)
  .map(x => x ** 2)
  |> console.log(?) || ?
  .filter(x => x > 100)

console.log(...) always returned undefined. So, console.log(...) || somethingElse will always cause the somethingElse to be evaluated and returned. This will effectivly cause the .filter() to be combined with the ?, which is exactly what we're wanting. |> console.log(?) || ?.filter(...)

This concept can also be used in a normal pipeline too:

const result = someData
  |> parse(?)
  |> filter(?)
  |> console.log(?) || ?
  |> format(?)

Not too shabby, eh?

This certainly satisfies my debugging needs - it's not difficult at all to put a ||? after the console.log, and it works in many scenarios.

Edit: I used || in these examples, because I often use || with console.log() when debugging expressions already. But, I guess a more general-purpose solution could be constructed by using the comma operator instead. This would allow us to have the tap operator, without extra syntax (though, I recognize that the comma operator isn't the most intuitive thing to use in production code).

const result = someData
  |> parse(?)
  |> filter(?)
  |> doSomethingWithValue(?), ?
  |> format(?)