Switch to config objects for operators with a lot of arguments.

[benlesh]

There are a few operators that have a lot of arguments, one example would be groupBy. This hurts readability a bit and also bites us later if we want to change or deprecate arguments.

So the idea is simple, introduce non-breaking changes to operators like groupBy to allow the passing of a config object to essentially provide "named arguments":

groupBy(fn1, fn2 fn3, fn4)

// becomes

groupBy({
  keySelector: fn1,
  resultSelector: fn2,
  durationSelector: fn3,
  subjectFactory: fn4,
})

(The names can be bikeshedded later, ideally to make it more terse but still readable)

[BioPhoton]

Hi @benlesh!

If this is still a thing I would create a list of all the operators that have enough arguments to get refactored to a config object.

I would collect:

• their name
• link to the source file
• their argument names and roughly the types
• suggestion for future naming (just as a placeholder. The real name is up to people that are responsible for it)
• structure of the future config object

I would provide it as markdown like this:

• groupBy
  Current Arguments:

  • keySelector: Function
  • elementSelector: Function
  • durationSelector: Function
  • subjectSelector: Function

  Future Config Object

  • Name: groupingConfig
  • Structure:

  {
    keySelector: Function
    elementSelector: Function
    durationSelector: Function
    subjectSelector: Function
  }

• otherOperator
  Current Arguments:

  • ...

  Future Config Object

  • ...

Let me know if the suggested approach would be helpful or if I can adapt anything.

[benlesh]

Thanks @BioPhoton.... we probably don't even need that level of detail. Just a list of the operators that have 3 or more arguments would be a great start.

[BioPhoton]

Could you suggest a naming pattern?
I.e. having Config as postfix or similar?

[BioPhoton]

Hi @benlesh!

Here the list of operators/functions that have 3 or more arguments (n means infinite)

Subjects

• ReplaySubject (3)

Creation Methode

• bindCallback (3)
• bindNodeCallback (3)
• combineLatest (n)
• concat (n)
• forkJoin (n)
• fromEvent (4)
• fromEventPattern (4)
• iif (3)
• merge (n)
• of (n)
• onErrorResumeNext (n)
• race (n)
• range (3)
• timer (3)
• zip (n)

Operators

• combineLatest (n)
• concat (n)
• count (3)
• endWith (n)
• every (3)
• expand (3)
• find (3)
• findIndex (3)
• groupBy (4)
• merge (n)
• mergeMap (3)
• mergeMapTo (3)
• mergeScan (3)
• onErrorResumeNext (n)
• pluck (n)
• publishReplay (3)
• race (n)
• shareReplay (3)
• single (3)
• startWith (n)
• tap (3)
• throttleTime (3)
• timeoutWith (3)
• windowTime (4)
• withLatestFrom (n)
• zip (n)