Side Effects

Effects are pure functions that take Data Model and Event Meta as parameters and return updated Data Model. Every FSM is locked onto oneself and cannot directly update the "outer world data" that is expressed by Data Model. To do so, Effects are invoked by Event Stack every time it repeats its cycle.

While every FSM can declare its own Effects, in fact they are invoked all at once, when (if) all FSMs have been already done with their Reducer loops and some Events have been emitted by Event Adapters. Only the emitted Events would be translated to Effects.

effect/<EFFECT_NAME> [<= (<META_KEY_LIST>)]