function splitJPath( jpath ) {
    return jpath.split( '.' );
}
Homebridge-MQTTThing JSON Codec (encoder/decoder)
codecs/json.js

Add configuration giving JSON 'path' for each property used by the accessory. For example:
"jsonCodec": {
    "properties": {
        "on": "state.power",
        "RGB": "state.rgb"
    },
    "fixed": { fixed properties object (global/default) },
    "fixedByTopic": {
        "topic1": { fixed properties object for topic1 },
        "topic2": { fixed properties object for topic2 }
    },
    "retain": true|false
}

Set retain: true in order to retain the object published for each topic, so that unchanged properties are published. 
(Default is retain: false, recreating object from fixed properties on every publish.)