Also, most web apps today brings side effects from...

# arrow

[Satyam Agarwal]

Also, most web apps today brings side effects from the very bottom. Like repositories (http call or db call), so most of the functions would have returning type as IO<A>.
That being said, do I gain anything except for direct imperative syntax (which i am not leveraging here) from a function with returning type IO if I execute my IOs in fx ?
for example :

import <http://arrow.fx.IO|arrow.fx.IO>
import arrow.fx.extensions.fx

fun someFun(): IO<Unit> = IO { println("hey") }
fun anotherFun(): IO<Unit> = IO { println("hey again") }

fun main() {
    someFun().followedBy(anotherFun()).unsafeRunSync()
}

fun mainMain() {
    IO
        .fx {
           someFun().followedBy(anotherFun()).bind()
        }
        .unsafeRunSync()

}

main()
mainMain()

[pakoito]

https://twitter.com/pacoworks/status/1153438984065998848

[pakoito]

Use IO only if suspend isn’t enough. Wrap suspend functions with effect. Parallelize with parMapN. Race IOs with raceN. Change threads with continueOn. Await IOs with prefix ! inside fx, and suspended inside a suspend function

[pakoito]

and then

[pakoito]

There are other classes to complement IO such as Promise (hot, single-result), Timer (sleep), Ref (atomic reference), MVar (concurrent queue size 1), Resource (acquire/release closeables), Semaphore (concurrent access to resource). They all use IO’s race/parallelism/cancelation.

[pakoito]

basically someFun should be suspend unless you have to do any of the things above

[pakoito]

and if you have a function that does those, i.e. run someFun in another thread, then you use IO

[pakoito]

same for kotlinx.coroutines, you only use launch, async, withContext and the rest of the family when suspend isn’t enough

[Satyam Agarwal]

aaaahhhhhh… Thank you so much 🙂 this clears so many clouds for me.