[Clarity Needed] Using input as params for "Run Custom Javascript" step in Workflow

[Skowt]

Is your feature request related to a problem? Please describe.
I want to be able to reuse a 'Run Custom Javascript' step by connecting different other blocks to it and sending a structured message to it. However, I can't target the input to the block. I'm not sure if this is meant to be possible or if it's just a way to trigger blocks in a certain sequence?

Describe the solution you'd like
In the 'arguments' section of the 'Run Custom Javascript' block, I'd like to include an argument which takes in the input passed to the 'in' port of the block, e.g. something like:

{{local.components.run-custom-javascript.in}} that would then return whatever the returnValue was from the previous block. I hope that makes sense.

Describe alternatives you've considered
N/A

Additional context

In the screenshot, the 'Run Custom Javascript' block should receive the output from either block attached to it and be able to use it in the arguments, without needing to specify specifically which block to get the output from.