Possibly better RxJS pipe typings?

[k-tten]

I know it's unlikely for someone to use 9+ operators in a pipe... but this is really bugging me...

pipe.ts' typings seems pretty huge, redundant, and unnecessary, and I want to help reduce it so:

• It's not huge, redundant, and unnecessary
• It can take 9+ operators and still produce the correct type

I made a simple prototype with this working in this gist (updated)

Currently, it takes in any amount of unary functions, and does the following:

• Validates if the unary functions are composable together (parameter and return types match)
• Spits out an unary function of the first one's parameter and the last one's return type
• If no arguments are present it spits out the identity function
• If only one argument is present it returns that argument

Thoughts, anyone?

Let me know if this can be possibly added.

[k-tten]

Uh oh, I've been testing my prototype and it seems to not handle the obvious case when there is only one operator 😅
No matter, I think it's an easy fix though

Now fixed + works with no arguments 👍

[k-tten]

Possibly related issue: #4177 ?