Here's a convoluted example but it should get the point across:

My followup question, is this the "best" way of doing this? Or is another technique more idiomatic?

depending on how complicated it gets,

Flow

may be useful, but it doesn't yet have good concurrency primitives, it's best for serial processing. You can emulate concurrent processing by using

.map { async { } }

and

.buffered

, but it's certainly more complex than this

if you have e.g. callbacks, other async tools, there are more efficient ways to wrap those as well

but if the only option is to block, this is the solution

What if we have a callback (or even a Promise)?