Set Interval in PureScript

Main.purs

module Main where

import Prelude

import Data.Maybe (Maybe(..))
import Effect (Effect)
import Effect.Console (log)
import Effect.Random as Random
import Effect.Ref as Ref
import Effect.Timer (clearInterval, setInterval)

main :: Effect Unit
main = do
  idRef <- Ref.new Nothing
  id <- setInterval 50 do
    log "Hello from setInterval"
    randomNumber <- Random.random
    if randomNumber < 0.2 then
      Ref.read idRef >>= case _ of
        Nothing -> pure unit
        Just id -> clearInterval id
    else
      pure unit
  Ref.write (Just id) idRef

spago.dhall

{-
Welcome to a Spago project!
You can edit this file as you like.
-}
{ name = "set-interval"
, dependencies =
    [ "console"
    , "effect"
    , "js-timers"
    , "maybe"
    , "psci-support"
    , "random"
    , "refs"
    ]
, packages = ./packages.dhall
, sources = [ "src/**/*.purs", "test/**/*.purs" ]
}