zigbee2mqtt/test/assets/external_extensions/cjs/exampleExtension.js

class Example {
    constructor(_zigbee, mqtt, _state, _publishEntityState, _eventBus) {
        this.mqtt = mqtt;
        this.mqtt.publish("example/extension", "call from constructor");
    }

    start() {
        this.mqtt.publish("example/extension", "call from start");
    }

    stop() {
        this.mqtt.publish("example/extension", "call from stop");
    }
}

module.exports = Example;