The Pop Message node is useful with all the nodes (like NLPjs Process , MC GraphQL node ) that overwrites the msg.payload of the Node-RED message, losing any reference with the original message from the chatbot user.

The Pop Message node restores the previous value of msg.payload overwritten by these nodes.

For example consider this flow when we want to query a database to check is the user is allowed to use the chatbot:

Check user credentials

The node MC GraphQL node is querying the database presenting the result in msg.payload overwriting the user’s message which is required in the rest of the flow. The Function node checks the result of the query and controls the flow: if the user is not allowed to use the chatbot the flow is redirected to the second pin and a “Not allowed” message is answered. If the user has the right permission the flow is redirected to the first pin and the user’s message (the previous value of msg.payload) is restored to be used in the rest of the flow (for example a parse node).

It’s possible to store the current message (msg.payload) with the Push message node, this is useful in all situations where the downstream node is overwriting the payload of the Node-RED message.

Warning: it doesn’t work across RedBot’s senders and receivers