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Manual NodeRED Runtime Node Js
znetsixe edited this page 2026-05-11 22:24:29 +02:00
Node-RED Runtime Node JS Manual (EVOLV Summary)
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Note
Reference page. Maintained for context; not regenerated by code. See Home for current top-level navigation.
Based on: https://nodered.org/docs/creating-nodes/node-js
Input Handler Contract
- Node-RED calls runtime handlers as
function(msg, send, done). - For compatibility, custom nodes should support fallback behavior when
sendis not provided. - Use
done()on successful completion anddone(err)on failure.
Output Routing Rules
- For single-output nodes:
send(msg)sends on output 1. - For multi-output nodes: pass an array with one slot per output, for example:
[msg, null, null]=> output 1 only[null, msg, null]=> output 2 only
- Always construct the outbound message first, then send it.
EVOLV Runtime Pattern
Recommended runtime input structure for src/nodeClass.js:
- Normalize
sendfallback. - Wrap
switch(msg.topic)intry/catch. - Route response messages to explicit output index with array format.
- Call
done()/done(err)consistently.
Common Failure Mode
- Sending a bare object in a multi-output context can hide intended port routing.
- In EVOLV nodes with 3 outputs (
process,dbase,parent), use explicit arrays for deterministic wiring behavior.