Message Enrichment Function for Chat Application

Context

You are building a PubNub Function that runs when messages are published to any chat channel. The function should look up the sender's profile from the key-value store and attach their display name and avatar URL to the message before it reaches subscribers. It should also add a server-side timestamp. If the user profile is not found, the message should still go through with default values.

Task

Write a PubNub Before Publish function (enrich-message.js) that:

1. Reads the sender's profile from persistent storage using the userId in the message
2. Adds the sender's display name and avatar to the message
3. Adds a server-side ISO timestamp to the message
4. Allows the message to proceed after enrichment
5. Handles errors gracefully without blocking message delivery

Expected Outputs

• An enrich-message.js file containing a complete PubNub Function ready for deployment.