zigbee2mqtt/test/assets/external_extensions/mjs/exampleExtension.mjs

export default class Example {
    constructor(zigbee, mqtt, state, publishEntityState, eventBus) {
        this.mqtt = mqtt;
        this.mqtt.publish('example/extension', 'call from constructor');
        this.counter = 0;
    }

    start() {
        this.mqtt.publish('example/extension', 'call from start');
        this.mqtt.publish('example/extension/counter', `start ${this.counter++}`);
    }

    stop() {
        this.mqtt.publish('example/extension', 'call from stop');
        this.mqtt.publish('example/extension/counter', `stop ${--this.counter}`);
    }
}