It there a way to limit the rate at which a flow e...

# coroutines

[tseisel]

It there a way to limit the rate at which a flow emits elements? My use case it to avoid running costly operations too often.
For example, given the following source flow:

val source = flow {
  emit("A")
  delay(100)
  emit("B")
  delay(50)
  emit("C")
  emit("D")
}

when applied a constraint of "max 1 element each 100ms", it should emit:
• "A" at t = 0ms
• "B" at t = 100ms
• "D" at t = 200ms

[Nick Allen]

Try:

source
    .conflate()
    .transform {
        emit(it)
        delay(100)
    }

Conflate will keep track of the most recently emitted value during the delay(100) from the previous value.

[rnett]

I think debounce does this in one step

[Nick Allen]

Debounce delays items and drops them if a new one is detected. So source.debounce(100) would maybe give "A" at 100ms and would emit "D" at 250ms.

[tseisel]

Many thanks @Nick Allen for your answer, it perfectly fits what I was looking for!
I've been searching for an equivalent of throttleLatest Rx operator for so long that I couldn't imagine it would be so simple 😵
The best part with your code is that we can also get throttleFirst by replacing conflate() with buffer(0, BufferOverflow.DROP_LATEST).