R.groupBy and flyd.transduce

[ghost]

Hi,

I like flyd and its interoperability with R transducers.

However, I have some troubles with R.groupBy that I don't have with the other transducers ( ie R.map )

`var stream = flyd.stream()
var transduce = flyd.transduce ( R.groupBy( x => String( x%2 ) ), stream )

flyd.map( console.log , transduce )

stream(1)
stream(2)

console.log( transduce() )
`

Output is undefined and not the result of groupBy

I try partitionBy from transducers-js and it seems to work well.

Thanks in advance for your reply

[nordfjord]

I did some investigation into this:

the transducer version of R.groupBy is implemented here: https://github.com/ramda/ramda/blob/master/source/internal/_xreduceBy.js

the @@transducer/step method is of particular interest, as you can see the last line is: return result. However result is not modified at all in the transducer.

Flyd's transduce implementation requires the step method to return a value which ramda's groupBy unfortunately does not.