Lightning Aura Components Developer Guide

Introducing Aura Components
Quick Start
Creating Components
Using Components
Communicating with Events
Communicating Across the DOM with Lightning Message Service
Create a Message Channel
Publish on a Message Channel
Subscribe to a Message Channel
Lightning Message Service Limitations
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.

Lightning Message Service Limitations

Keep the following in mind when working with Lightning message service.
Supported Experiences
Lightning message service supports only the following experiences:
  • Lightning Experience standard navigation
  • Lightning Experience console navigation
  • Salesforce mobile app for Aura and Lightning Web Components, but not for Visualforce pages
  • Lightning components used in Experience Builder sites.

    Lightning Message Service doesn't work with Salesforce Tabs + Visualforce sites or with Visualforce pages in Experience Builder sites.

    Note

Aura Components That Don’t Render Aren’t Supported
Lightning message service only supports Aura components that render. You can’t use lightning:messageChannel in an Aura component that uses the background utility item interface. Similarly, Aura components that use lightning:messageChannel can’t call Lightning Message Service methods in the init lifecycle handler because the component hasn’t rendered.
lightning:messageChannel Must Be a Child of aura:component
In a custom Aura component, lightning:messageChannel must be an immediate child of the aura:component tag. It can’t be nested in an HTML tag or another component.

For example, the following code renders without a problem.

1<aura:component>
2  <lightning:messageChannel type="myMessageChannel__c" />
3  <lightning:card>...</lightning:card>
4</aura:component>

This code throws an error when the Aura component tries to render.

1<aura:component>
2  <lightning:card>
3    <lightning:messageChannel type="myMessageChannel__c" />
4  </lightning:card>
5</aura:component>
Messages are Constrained by iframe Boundary
If your component uses Lightning message service to publish a message, that message is constrained by any iframe boundary. To work around this limitation, use the sforce.one.subscribe() and sforce.one.unsubscribe() methods.
Avoid Dynamically Creating lightning:messageChannel Components in Aura
Do not usecreateComponent() to dynamically create a lightning:messageChannel component in Aura. Dynamically created components may not work as expected. For information on supported ways to create a lightning:messageChannel component, see Create a Message Channel.