32 lines
1.1 KiB
Markdown
32 lines
1.1 KiB
Markdown
|
# Node-RED Runtime Node JS Manual (EVOLV Summary)
|
||
|
|
|
||
|
|
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 `send` is not provided.
|
||
|
|
- Use `done()` on successful completion and `done(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`:
|
||
|
|
|
||
|
|
1. Normalize `send` fallback.
|
||
|
|
2. Wrap `switch(msg.topic)` in `try/catch`.
|
||
|
|
3. Route response messages to explicit output index with array format.
|
||
|
|
4. 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.
|