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This module provides the Effect type, which is used to represent native effects. The Effect type provides a typed API for effectful computations, while at the same time generating efficient JavaScript.

A native effect. The type parameter denotes the return type of running the effect, that is, an Effect Int is a possibly-effectful computation which eventually produces a value of the type Int when it finishes.

Type synonym for using Effect as an effect.

effect :: forall a n. Named n { cause :: a, effect :: a } -> Named (Effect n) a

effect :: forall props a. String -> Effect (a -> a) -> FormBuilder props a a

A dummy form that, whenever the specified key changes, performs an effect. It sets the form data to the result of the effect and returns it.

An Effect with base type st.

effect0 :: forall b a. String -> a -> b

The base functor of the Effect free monad.

effectful :: forall f output. Effectful f output => f -> output

This module defines the Ref type for mutable value references, as well as actions for working with them.

You'll notice that all of the functions that operate on a Ref (e.g. new, read, write) return their result wrapped in an Effect. Working with mutable references is considered effectful in PureScript because of the principle of purity: functions should not have side effects, and should return the same result when called with the same arguments. If a Ref could be written to without using Effect, that would cause a side effect (the effect of changing the result of subsequent reads for that Ref). If there were a function for reading the current value of a Ref without the result being wrapped in Effect, the result of calling that function would change each time a new value was written to the Ref. Even creating a new Ref is effectful: if there were a function for creating a new Ref with the type forall s. s -> Ref s, then calling that function twice with the same argument would not give the same result in each case, since you'd end up with two distinct references which could be updated independently of each other.

Note: Control.Monad.ST provides a pure alternative to Ref when mutation is restricted to a local scope.

EffectFnAff :: forall a. (EffectFn2 (EffectFnCb Error) (EffectFnCb a) EffectFnCanceler) -> EffectFnAff a

effectCrash :: forall a. String -> Effect a

effectfully :: forall st eff a. (st -> Aff eff a) -> Effect eff st a

Perform a Control.Monad.Aff action and return a result.

effectsOver :: forall @f @a. Functor f => FreeS f a -> Array (f Unit)

Collect every possible effect into an Array.

effectToPoll :: Effect ~> Poll

Turn an Effect into a poll

effectsUnder :: forall @f @a. Functor f => FreeS f a -> Array (f Unit)

Collect every required effect into an Array.

effectScatter :: forall m i. Monad m => (CommandsT EffectScatterI m) ~> (CommandsT (effectScatter :: I | i) m)