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node.jsnode-red

Node-red not detecting null value

I am trying to build a flow, that reads sensor data and transfers by CANBUS. Sometimes, null data is coming what I mean is tempInt or ldrInt could be null. 

   var msg2 = {
   payload:
       {
           "$class": "org.acme.testnetwork.UpdateSensorData",
           "sampDevice": "houseMehmet",
           "newTempVal": tempInt,
           "newLightVal": ldrInt,
           "timeStamp": Date().toString()
       }
   };

Although I can access msg.payload.newLightVal and set it to any value, in the case that its value is null, the control statement such below fails.

if(msg.payload.newLightVal===null){
    msg.payload.newLightVal = -1 ;
}
Solution

  • Are you sure that tempInt and ldrInt are null and not undefined . I think they may be undefined in which case replace === with == in the if statement i.e

    if(msg.payload.newLightVal==null)

    Edit : Since the msg.payload.newLightVal is NaN , this should be the if clause

     if(msg.payload.newLightVal==null || isNaN(msg.payload.newLightVal))