I am trying to pull 2 parameters from an LMS message. Currently they are coming in as null at the way I am grabbing them. The publish and subscribe methods work, as I threw console statements to track everything, but I am seeing an error when I try to assign the vars as null from my apex class that uses them..

Publisher JS:

     let selectedIdValue = event.currentTarget.getAttribute("data-key");
     this.newMediaId = event.currentTarget.getAttribute("data-key");
     const message = {
          mediaId: selectedIdValue, mediaList:this.mediaList
     publish(this.messageContext, navigationMessageChannel, message);
     publish(this.dataMessageContext, dataMessageChannel, message);

Handler JS:

subscription = null;
              this.subscription = subscribe(
                    (message) => this.handleMessage(message),
                    {scope: APPLICATION_SCOPE}
     this.mediaId = message.mediaId;
     thhis.mediaList = message.mediaList;

also tried :

         this.mediaId = message.parameters.mediaId;
         thhis.mediaList = message.parameters.mediaList;
  • also tried message.details.mediaId; and message.detail.mediaId; Feb 10 at 1:46
  • How are you handling subscribing to the message channel? Are you passing in {message} => this.handleMessage(message)? What does console.log(message) show in handleMessage? Feb 10 at 3:35
  • @KrisGoncalves Yes I am handling the message channel similar to this developer.salesforce.com/docs/component-library/documentation/… when I console.log(JSON.stringify(message) I get the ' "mediaId" : "123", "mediaList" :"1234" ' Feb 10 at 3:37
  • Can you also add the method that subscribes to this message-channel? Feb 10 at 3:38
  • @SachinHooda sure, give me a moment to add Feb 10 at 3:39

1 Answer 1


I solved the issue, the issue was that the mediaList and mediaID would become null because of the connectedcallback they were in. I moved the function callout to after the assigning of vars and it fixed it.

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