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
Handling Bubbled or Captured 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.

Handling Application Events

Use <aura:handler> in the markup of the handler component.

For example:

1<aura:handler event="c:appEvent" action="{!c.handleApplicationEvent}"/>

The event attribute specifies the event being handled. The format is namespace:eventName.

The action attribute of <aura:handler> sets the client-side controller action to handle the event.

The handler for an application event won’t work if you set the name attribute in <aura:handler>. Use the name attribute only when you’re handling component events.

Note

In this example, when the event is fired, the handleApplicationEvent client-side controller action is called.

Event Handling Phases

The framework allows you to handle the event in different phases. These phases give you flexibility for how to best process the event for your application.

Application event handlers are associated with the default phase. To add a handler for the capture or bubble phases instead, use the phase attribute.

Get the Source of an Event

In the client-side controller action for an <aura:handler> tag, use evt.getSource() to find out which component fired the event, where evt is a reference to the event. To retrieve the source element, use evt.getSource().getElement().