Nodejs - async function - TypeError: Cannot set property 'temperature' of undefined

Question

JavaScript beginner here, I'm trying to get something going in Nodejs using hap-nodejs module.

My Main file looks like this:

const config = require('../config');
const Syno = require('synology');
const docker = new Docker(config.dockerode);
const storage = require('node-persist');
const os = require('os');
storage.initSync();
const {Bridge, uuid, Categories} = require('hap-nodejs');
const TemperatureSensorAccessory = require('./TempGageAccessory');

const name = config.bridge.deviceName.replace('$hostname', os.hostname()).replace(/\./, ' ');
const bridge = new Bridge(name, uuid.generate('Remote Bridge'));

bridge.publish({
    username: config.bridge.mac,
    port: config.bridge.port,
    pincode: config.bridge.pincode,
    category: Categories.BRIDGE
});

async function publishSynology()
{
    const dev = new TemperatureSensorAccessory('NAS_SYS_TEMP');
    bridge.addBridgedAccessories({
        accessory: dev.getAccessory()
    });
}

publishSynology();

and my /TempGageAccessory.js file where the problem is this one here:

const {Accessory, Service, Characteristic, uuid, Categories} = require('hap-nodejs');
const Syno = require('synology');
const {emitter, docker} = require('./DockerKit');

module.exports = class TemperatureSensorAccessory {
    constructor(name) {
        console.log('Constructing ' + name);
        this.TemperatureSensor = {
            name,
            model: 'Synology NAS Temperature Sensor',
            category: Categories.SENSOR,
            description: name,
            setTemperature:  function () {
                let syno = new Syno({
                    host    : '10.0.0.1',
                    port    : '5656',
                    secure  : 'true',
                    user    : 'user',
                    password: 'password'
                });

                syno.query('/webapi/entry.cgi', {
                    api    : 'SYNO.Core.System',
                    version: 1,
                    method : 'info'
                }, function(err, data) {
                    if (err) return console.error(err);
                    console.log(data['data']['sys_temp']);
                    this.temperature = parseFloat(data['data']['sys_temp']);
                    return parseFloat(data['data']['sys_temp']);
                });
            },
            temperature: 0.0,
            getTemperature: async function () {
                console.log('[' + name + '] Getting Temperature' + this.temperature);
                return this.temperature;
            },
            uuid: uuid.generate('hap-nodejs:accessoires:temperaturesensor:synology:' + name),
            accessory: null
        };
        const that = this;
        that.TemperatureSensor.setTemperature();
        that.getAccessory().getService(Service.TemperatureSensor).getCharacteristic(Characteristic.On).updateValue(that.TemperatureSensor.temperature);

     }

    getAccessory() {
        if (!this.TemperatureSensor.accessory) {
            let acc;
            acc = new Accessory(this.TemperatureSensor.name, this.TemperatureSensor.uuid);
            acc.username = '8a:bc:80:74:de:16';
            acc.pincode = '123-45-678';
            acc
                .addService(Service.TemperatureSensor, this.TemperatureSensor.name)
                .getCharacteristic(Characteristic.CurrentTemperature)
                .on('get', async(cb) => {

                    // return our current value
                    cb(null, await this.TemperatureSensor.getTemperature());
                  });
            this.TemperatureSensor.accessory = acc;
            return acc;
        } else return this.TemperatureSensor.accessory;
    }
};

I got everything almost there, my rest call is working fine and I'm returning my data. But when I try to assign the result of my query to property temperature I get the following error:

TypeError: Cannot set property 'temperature' of undefined

Please, can someone explain what I'm doing wrong ? I'm no Javascript Developer, first time playing with it coming from C#/Python.

Looks like this one ~ [How to access the correct `this` inside a callback?](https://stackoverflow.com/questions/20279484/how-to-access-the-correct-this-inside-a-callback) — Phil, Apr 27 '20 at 00:19

score 0 · Answer 1 · answered Apr 27 '20 at 19:47

0

Beginner error, fixed by refereeing to the correct object.

answered Apr 27 '20 at 19:47

ddmunhoz

31
4

Nodejs - async function - TypeError: Cannot set property 'temperature' of undefined

1 Answers1