Operator: processor
A processor modifies the incoming signal and emits it. It does not interact with external world. The process function takes a callback function to emit an error signal or the modified signal.
Signature
NS.processor(comment : string, inputs : map, outputs : map, process : function) : Node
Arguments
| Arguement | Type | Description |
|---|---|---|
| comment | string | optional, the comment of the processor |
| inputs | map | optional, the input description |
| outputs | map | optional, the output description |
| process | function | optional, the process function, it takes a callback function as the second argument, which accepts an error and new signal. If the error argument is not empty, an error signal will be sent, otherwise, the new signal will be sent |
processSync function signature:
function process(signal : Signal, done : function) : void
done argument is a callback function with signature:
function done(error : Error, newSignal : Signal) : void
If error argument is not null, an ERROR signal is sent to stream otherwise the new signal is emitted.
Return
| Type | Description |
|---|---|
| Node | the processor node |
Create an async processor
const ns = collar.ns('collarjs.demo.processor')
const proc = ns.processor("double the payload",
( signal, done ) => {
let v = signal.get('value');
done(null, signal.new({value: v * 2}));
});