Lightning message system pass data from lwc to aura

Question

I am trying to pass data from lwc to aura via LMS. How can i do it? I dont really understand what to do in aura.

handleReceiveMessage executed, but i cannot get data.

LWC

import { LightningElement, wire } from 'lwc';
import messageChannel from '@salesforce/messageChannel/SampleMessageChannel__c';
import {publish, MessageContext} from 'lightning/messageService'

export default class Publisher extends LightningElement {

    @wire(MessageContext)
    messageContext;

    handleButtonClick(event) {
        let message = {messageText: 'This is a test'};
        publish(this.messageContext, messageChannel, message);
    }
}

Aura

    <aura:component access="global" implements="lightning:availableForFlowScreens">
    
    <aura:attribute  name="messageText" type="String" />
      <lightning:messageChannel type="SampleMessageChannel__c"
                              aura:id="SMC" 
                              scope="APPLICATION"
                              onMessage="{!c.handleReceiveMessage}"
                         />
    <div>{!messageText}</div>
    </aura:component>



    ({
        handleReceiveMessage: function (component, event, helper) {
                if (event != null) {
                    const message = event.getParam('messageText');
                    component.set("v.messageText", 'Message: ' + message );
                }
            }
    });

Answer 1

You need to specify the correct scope in order to receive the message:

<lightning:messageChannel type="SampleMessageChannel__c"
                          aura:id="SMC" 
                          scope="APPLICATION"
                          onMessage="{!c.handleReceiveMessage}"
                     />