Decoding a float value in a payload function

Application Development
16

var msg2 = { payload: msg.payload.length };
msg2.payload = JSON.parse(msg.payload);
msg2.payload = new Buffer(msg2.payload.payload, ‘base64’).toString(‘hex’);
var lat = Buffer(msg2.payload, ‘hex’).readFloatLE(0);
var lon = Buffer(msg2.payload, ‘hex’).readFloatLE(4);
msg2.payload= “[{“lat”:” + lat + “,“lng”:” + lon + “}]”;//"{“lat”:lat,“lng”:lon};
return msg2;

This is how I am decoding the ttn payload via node-red. This assumes that the payload I am getting from ttn via mqtt is an 8 byte payload, coming out of the node-red mqtt node in base64, with the first four bytes being one float, and the second four bytes being the second float.

If you are trying to decode a raw 8 byte value, it’s even easier:

var lat = new Buffer(msg.payload).readFloatLE(0);
var lon = new Buffer(msg.payload).readFloatLE(4);
msg.payload= “[{“lat”:” + lat + “,“lng”:” + lon + “}]”;//"{“lat”:lat,“lng”:lon};
return msg;

I hate javascript and am terrible at doing anything with it, so there is probably a more efficient way to do this.

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