Operator: filter
Filter is the data flow control node, it allows signal to pass under certain conditions
Signature
NS.filter(comment : string, inputs : map, outputs : map, accept : function) : Node
Alias:
NS.when(comment : string, inputs : map, outputs : map, accept : function) : Node
Arguments
| Arguement | Type | Description |
|---|---|---|
| comment | string | optional, the comment of the sensor |
| inputs | map | optional, the input description |
| outputs | map | optional, the output description |
| accept | function | the condition function, allow signal pass if return true, otherwise return false |
accept function signature:
function accept(signal : Signal) : Boolean
Return
| Type | Description |
|---|---|
| Node | the filter node |
Create a filter
const ns = collar.ns('collarjs.demo.sensor');
const input = ns.input('input');
input
.filter(s => {
return s.get('v') % 2 === 0;
})
.do(s => console.log(s.payload));
input.push({v: 1}); // --> output nothing
input.push({v: 2}); // --> {v: 2}