Automatic Next Actions

After propose - receive - model - render view has completed, you might want to trigger another proposal automatically. You would decide depending on the last proposal and the resulting model.

To add a function that can trigger an automatic next action, use the nextAction property when creating a component. Meiosis passes a single object parameter with the model, proposal, and either propose or the actions object to the function.

In the rocket-laucher example, the nextAction function keeps the countdown going or launches the rocket:

ref.nextAction = function(context) {
  if (ref.state.counting(context.model)) {
    if (context.model.counter > 0) {
      context.actions.decrement(context.model.counter);
    }
    else if (context.model.counter === 0) {
      context.actions.launch();
    }
  }
};

Specify the nextAction when creating the component:

var Main = createComponent({
  // ...
  nextAction: nextAction
});

Meiosis calls the nextAction after receive has completed and the view has refreshed. Notice that the nextAction doesn't need to return anything. It should either trigger another action by calling propose(...) or actions.someAction(...), or do nothing.

Examples

The rocket-laucher, temperatures, and todo-list examples use a nextAction function.