Lightning Aura Components Developer Guide
jSubscribe to a Message Channel
To subscribe to a message channel, create a handler method to run when it receives a
message.
Example
The lmsSubscriberAuraComponent from the github.com/trailheadapps/lwc-recipes repo shows how to
subscribe and unsubscribe from a message channel.
In this example, we define an Aura component called myNewComponent that contains the custom message channel, SampleMessageChannel__c. The lightning:messageChannel component's onMessage attribute calls the handleChanged method in the client-side controller.
By default, communication over a message channel can occur only between components in
an active navigation tab, an active navigation item, or a utility item. Utility
items are always active. A navigation tab or item is active when it’s selected.
Navigation tabs and items include:
- Standard navigation tabs
- Console navigation workspace tabs
- Console navigations subtabs
- Console navigation items
To receive messages on a message channel from anywhere in the application, use
lightning:messageChannel's optional
parameter, scope. Set scope to the value "APPLICATION".
The component myNewComponent detects a new message and updates the display value.
Write the handler in your component's client-side controller. The handleChanged method fires when there is a new message. It checks whether there is a payload in the message, and if so, assigns the new data to the v.recordValue attribute. The lightning:formattedText element updates to display the new value.