Event Observer (4h)
- Eden Duong
An event has two parts. In the core, we dispatch (or fire) an event to create customize point. In the plugin, we subscribe (or listen) to execute our custom code.
Fire an event
import {fire} from "../src/event-bus";
...
// Fire an event to allow modify logic
fire('[name_of_event]', [event_data]);
Listen an event
import {listen} from "../src/event-bus";
...
// Listen an event
listen('[name_of_event]', (eventData) => {
// Custom logic here
}, [listener_tag]);
name_of_event: must be same as
firename_of_eventobserver: is a function that receive
eventDataparameter fromfireeventlistener_tag: to identify listener. Listeners that registed with same tag is overrided. Only last observer with same tag (and same name_of_event) is active.
Event naming
To manage events easier, we should naming events following this format [object_type]_[object_name]_[method/action]_[event_position]
For example, an event name model_customer_save_after means 1. object_type: model 2. object_name: customer 3. method/action: save 4. event_position: after
Recommended Reading
Exercise: Use event/observer, after add product to cart, show successfully message , quantity of product added