Lightning Aura Components Developer Guide

Introducing Aura Components
Quick Start
Creating Components
Using Components
Communicating with Events
Actions and Events
Handling Events with Client-Side Controllers
Component Events
Application Events
Application Event Propagation
Create Custom Application Events
Fire Application Events
Handling Application Events
Application Event Example
Event Handler Behavior for Active Components
Event Handling Lifecycle
Advanced Events Example
Firing Events from Non-Aura Code
Events Best Practices
Events Fired During the Rendering Lifecycle
Events Handled in the Salesforce Mobile App and Lightning Experience
System Events
Communicating Across the DOM with Lightning Message Service
Creating Apps
Styling Apps
Developing Secure Code
Using JavaScript
Working with Salesforce Data
Testing Components
Debugging
Performance
Reference
PDF

Note: This release is in preview. Features described here don’t become generally available until the latest general availability date that Salesforce announces for this release. Before then, and where features are noted as beta, pilot, or developer preview, we can’t guarantee general availability within any particular time frame or at all. Make your purchase decisions only on the basis of generally available products and features.

Fire Application Events

Application events follow a traditional publish-subscribe model. An application event is fired from an instance of a component. All components that provide a handler for the event are notified.

Register an Event

A component registers that it may fire an application event by using <aura:registerEvent> in its markup. The name attribute is required but not used for application events. The name attribute is only relevant for component events. This example uses name="appEvent" but the value isn’t used anywhere.

1<aura:registerEvent name="appEvent" type="c:appEvent"/>

Fire an Event

Use $A.get("e.myNamespace:myAppEvent") in JavaScript to get an instance of the myAppEvent event in the myNamespace namespace.

The syntax to get an instance of an application event is different than the syntax to get a component event, which is cmp.getEvent("evtName").

Note

Use fire() to fire the event.

1var appEvent = $A.get("e.c:appEvent");
2// Optional: set some data for the event (also known as event shape)
3// A parameter’s name must match the name attribute
4// of one of the event’s <aura:attribute> tags
5//appEvent.setParams({ "myParam" : myValue });
6appEvent.fire();

Events Fired on App Rendering

Some events are automatically fired when an app is rendering. For more information, see Events Fired During the Rendering Lifecycle.