<@U84KF4UHM> if you want your code reviewed, you gotta put up your attempt to solve the problem

# codereview

[Shawn]

@ecampolo if you want your code reviewed, you gotta put up your attempt to solve the problem

[ecampolo]

Done!

[Shawn]

Okay!

[Shawn]

Is there a reason you’re using forEach over map or flatMap?

[ecampolo]

because if I use flatmap and map i would lose those entries whose array are empty

[Shawn]

@ecampolo?

[ecampolo]

since map would omit those foo with empty bars

[Shawn]

That’s true if you use them in a certain way, but that doesn’t mean they’re not useful to your problem

[Shawn]

You’re right that map alone would avoid iterating over empty lists instead of creating a FooBar with null - in this case I don’t think it’s possible to get away without using some kind of conditional logic

[ecampolo]

that's a shame haha

[ecampolo]

i was eager to find a one liner with some FP sauce

[ecampolo]

tried with groupingBy

[Shawn]

the most succinct snippet I could come up with looks like this

foos.flatMap { foo ->
    when {
      foo.bars.isEmpty() -> listOf(FooBar(foo, null))
      else -> foo.bars.map { FooBar(foo, it) }
    }
  }

[ecampolo]

not bad

[ecampolo]

let me see

[ecampolo]

the only thing I see is that we are creating multiple arrays

[ecampolo]

but i dont think is that bad in terms of memory consumption, i will try it

[Shawn]

unless n is huge, I doubt it’ll be too problematic

[ecampolo]

it is quite large

[ecampolo]

i will test it thou

[ecampolo]

i like the approach

[ecampolo]

thank you

[Shawn]

a less readable but maybe more efficient approach might look like this:

foos.flatMap { foo ->
  (if (foo.bars.isEmpty()) listOf(null) else foo.bars)
      .map { FooBar(foo, it) }
}