# How to solve the error "socket.on is not a function"

**URL:** <https://community.homey.app/t/how-to-solve-the-error-socket-on-is-not-a-function/121242>\
**Category:** Questions & Help\
**Tags:** app, homey-pro\
**Created:** [November 22, 2024, 1:42am UTC](https://community.homey.app/t/how-to-solve-the-error-socket-on-is-not-a-function/121242 "2024-11-22T01:42:55Z")\
**Posts on this page:** 8\
**Page:** 1

<div class="post-metadata">

**Author:** ![chuck\_rui](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/chuck_rui/32/115662_2.png) [@chuck\_rui](https://community.homey.app/u/chuck_rui)\
**Post date:** [November 22, 2024, 1:42am UTC](https://community.homey.app/t/how-to-solve-the-error-socket-on-is-not-a-function/121242/1 "2024-11-22T01:42:55Z")

</div>

I want to add a device based on the 433MHz protocol to Homey, and I have already created an app and a driver. However, when I try to pair the device, I get an error message when I click on the driver that says “socket.on is not a function.” This means that the front-end and back-end cannot connect through this socket when there is no device sending the pairing protocol?

 ![b604a0370dea1fc7806a9ac5179fb49](https://us1.discourse-cdn.com/flex025/uploads/athom/original/3X/b/2/b21cb6fa2499d444bf50d52d38fceebb574cad0e.jpeg)

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<div class="post-metadata">

**Author:** ![robertklep](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/robertklep/32/160628_2.png) [@robertklep](https://community.homey.app/u/robertklep)\
**Post date:** [November 22, 2024, 5:27am UTC](https://community.homey.app/t/how-to-solve-the-error-socket-on-is-not-a-function/121242/2 "2024-11-22T05:27:22Z")

</div>

This is a bug in your driver.

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<div class="post-metadata">

**Author:** ![chuck\_rui](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/chuck_rui/32/115662_2.png) [@chuck\_rui](https://community.homey.app/u/chuck_rui)\
**Post date:** [November 22, 2024, 5:40am UTC](https://community.homey.app/t/how-to-solve-the-error-socket-on-is-not-a-function/121242/3 "2024-11-22T05:40:41Z")

</div>

Is there a solution? Is it because there’s something wrong with my code? Or is it something else…

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<div class="post-metadata">

**Author:** ![robertklep](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/robertklep/32/160628_2.png) [@robertklep](https://community.homey.app/u/robertklep)\
**Post date:** [November 22, 2024, 5:41am UTC](https://community.homey.app/t/how-to-solve-the-error-socket-on-is-not-a-function/121242/4 "2024-11-22T05:41:19Z")

</div>

There’s something wrong with your code. But without sharing it nobody will be able to point out the problem.

---

<div class="post-metadata">

**Author:** ![chuck\_rui](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/chuck_rui/32/115662_2.png) [@chuck\_rui](https://community.homey.app/u/chuck_rui)\
**Post date:** [November 22, 2024, 7:19am UTC](https://community.homey.app/t/how-to-solve-the-error-socket-on-is-not-a-function/121242/5 "2024-11-22T07:19:03Z")

</div>

device.js

```auto
'use strict';

const Homey = require('homey');

module.exports = class MyDevice extends Homey.Device {

  /**
   * onInit is called when the device is initialized.
   */
  async onInit() {
    this.log('Dimmer Device initialized:', this.getName());

    this.registerCapabilityListener('onoff', this.onCapabilityOnoff.bind(this));
    this.registerCapabilityListener('dim', this.onCapabilityDim.bind(this));
    this.log('Capability listeners registered for onoff and dim');
  }

  async onCapabilityOnoff(value) {
    this.log('Received onoff command:', value ? 'Turn on' : 'Turn off');
    const command = value ? '00000001' : '00000000';
    this.sendSignal(command);
  }

  async onCapabilityDim(value) {
    const dimLevel = Math.round(value * 15).toString(2).padStart(8, '0');
    this.log('Received dim command:', value, 'Calculated dim level:', dimLevel);
    this.sendSignal(dimLevel);
  }

  sendSignal(command) {
    const payload = `00000001${this.getData().id.toString(2).padStart(8, '0')}${command}`;
    const binaryPayload = payload.split('').map(bit => parseInt(bit, 10));

    this.log('Sending signal with payload:', binaryPayload);

    this.getSignal().tx(binaryPayload, (err) => {
      if (err) {
        this.error('Error sending signal:', err);
      } else {
        this.log('Signal sent successfully:', binaryPayload);
      }
    });
  }

  getSignal() {
    return Homey.Signal433.getSignal('dimmer_signal');
  }

  /**
   * onAdded is called when the user adds the device, called just after pairing.
   */
  async onAdded() {
    this.log('MyDevice has been added');
  }

  /**
   * onSettings is called when the user updates the device's settings.
   * @param {object} event the onSettings event data
   * @param {object} event.oldSettings The old settings object
   * @param {object} event.newSettings The new settings object
   * @param {string[]} event.changedKeys An array of keys changed since the previous version
   * @returns {Promise<string|void>} return a custom message that will be displayed
   */
  async onSettings({ oldSettings, newSettings, changedKeys }) {
    this.log('MyDevice settings were changed');
  }

  /**
   * onRenamed is called when the user updates the device's name.
   * This method can be used this to synchronise the name to the device.
   * @param {string} name The new name
   */
  async onRenamed(name) { 
    this.log('MyDevice was renamed');
  }

  /**
   * onDeleted is called when the user deleted the device.
   */
  async onDeleted() {
    this.log('MyDevice has been deleted');
  }

};

```

driver.compose.json

```auto
{
  "name": {
    "en": "Light bulb"
  },
  "class": "light",
  "capabilities": [
    "dim",
    "onoff"
  ],
  "platforms": [
    "local"
  ],
  "connectivity": [
    "rf433"
  ],
  "images": {
    "small": "{{driverAssetsPath}}/images/small.png",
    "large": "{{driverAssetsPath}}/images/large.png",
    "xlarge": "{{driverAssetsPath}}/images/xlarge.png"
  },
  "pair": [
  {
    "id": "list_devices",
    "template": "list_devices",
    "navigation": {
      "next": "add_devices"
    }
  },
  {
    "id": "add_devices",
    "template": "add_devices"
  }
  ]
}

```

driver.js

```auto
'use strict';

const Homey = require('homey');

module.exports = class MyDriver extends Homey.Driver {
  async onInit() {
    this.log('433 MHz Dimmer Driver initialized');
  }

  onPair(socket) {
    if (!socket || typeof socket.on !== 'function') {
      this.error('Socket initialization failed: socket.on is not a function.');
      return;
    }
  
    this.log('Socket initialized successfully for pairing.');
  
    let devices = []; 
  
    socket.on('list_devices', async (data, callback) => {
      this.log('Listening for devices during pairing...');
      devices = [];
  
      try {
        const signal = this.homey.rf.getSignal433('dimmer_signal');
  
        const handlePayload = (payload) => {
          const decodedSignal = this.decodeSignal(payload);
          this.log('Decoded signal:', decodedSignal);
  
          if (this.isValidDevice(decodedSignal)) {
            const newDevice = { 
              name: `Dimmer ${decodedSignal.id}`, 
              data: { id: decodedSignal.id } 
            };
            if (!devices.find((device) => device.data.id === decodedSignal.id)) {
              devices.push(newDevice);
              this.log('Device added:', newDevice);
            }
          }
        };
  
        signal.on('payload', handlePayload);
  
        setTimeout(() => {
          signal.removeListener('payload', handlePayload); 
          this.log('Devices found:', devices);
          callback(null, devices.length > 0 ? devices : []); 
        }, 10000);
      } catch (err) {
        this.error('Error during pairing process:', err);
        callback(null, []); 
      }
    });
  
    socket.on('add_device', (device, callback) => {
      this.log('Device added successfully:', device);
      callback(null, device);
    });
  }
  

  decodeSignal(payload) {
    const binaryString = payload.join('');
    const type = binaryString.substring(0, 8); 
    const id = binaryString.substring(8, 16); 
    const command = binaryString.substring(16, 24); 

    this.log(`Decoded Signal - Type: ${type}, ID: ${id}, Command: ${command}`);

    return {
      type: parseInt(type, 2),
      id: parseInt(id, 2),
      command,
    };
  }

  isValidDevice(decodedSignal) {
    const isValid = decodedSignal.type === 1; 
    this.log(`Device validation result: ${isValid}`);
    return isValid;
  }
};

```

Please help me with it, because I’ve been stuck here for too long ☹  
It is worth mentioning that the template folder under drivers in the.homeycompose directory of my app project is empty, do I need to add list\_devices.html and add\_devices.html files myself?  
I add list\_devices.html and add\_devices.html file to .homeycompose/drivers/template such as below  
list\_devices.html

```auto
<div class="step">
    <h1>Discovering Devices</h1>
    <p>Searching for 433MHz devices...</p>
    <style>
      .spinner {
        margin: 20px auto;
        border: 8px solid #f3f3f3;
        border-top: 8px solid #3498db;
        border-radius: 50%;
        width: 40px;
        height: 40px;
        animation: spin 1s linear infinite;
      }
  
      @keyframes spin {
        0% {
          transform: rotate(0deg);
        }
        100% {
          transform: rotate(360deg);
        }
      }
      .message {
        text-align: center;
        font-size: 16px;
        color: #666;
        margin-top: 20px;
      }
    </style>
    <div class="spinner"></div>
    <div class="message">
      {{#if devices.length}}
        <p>New devices found. Select a device to continue.</p>
      {{else}}
        <p>No devices found. Please try again or ensure your device is in pairing mode.</p>
      {{/if}}
    </div>
  </div>
  

```

add\_devices.html

```auto
<div class="step">
    <h1>Adding Device</h1>
    <p>Connecting your 433MHz device to Homey...</p>
    <style>
      .spinner {
        margin: 20px auto;
        border: 8px solid #f3f3f3;
        border-top: 8px solid #3498db;
        border-radius: 50%;
        width: 40px;
        height: 40px;
        animation: spin 1s linear infinite;
      }
  
      @keyframes spin {
        0% {
          transform: rotate(0deg);
        }
        100% {
          transform: rotate(360deg);
        }
      }
      .message {
        text-align: center;
        font-size: 16px;
        color: #666;
        margin-top: 20px;
      }
    </style>
    <div class="spinner"></div>
    <div class="message">
      <p>Please wait while the device is being added...</p>
    </div>
  </div>
  

```

And then i clicked the driver in homey app it will show below error

 ![image](https://us1.discourse-cdn.com/flex025/uploads/athom/original/3X/6/d/6d9a22a82c882df8023c9f9bf02a6522899246c4.png)

---

<div class="post-metadata">

**Author:** ![robertklep](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/robertklep/32/160628_2.png) [@robertklep](https://community.homey.app/u/robertklep)\
**Post date:** [November 22, 2024, 8:30am UTC](https://community.homey.app/t/how-to-solve-the-error-socket-on-is-not-a-function/121242/6 "2024-11-22T08:30:06Z")

</div>

> [@chuck\_rui](#):
>
> ```auto
> onPair(socket) {
> ...
> socket.on('list_devices', ...)
> }
> 
> ```

This is SDKv2 code, and SDKv2 has been deprecated for a while now. The SDKv3 equivalent [can be found here](https://apps.developer.homey.app/the-basics/devices/pairing/system-views/devices-list).

---

<div class="post-metadata">

**Author:** ![chuck\_rui](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/chuck_rui/32/115662_2.png) [@chuck\_rui](https://community.homey.app/u/chuck_rui)\
**Post date:** [November 22, 2024, 8:44am UTC](https://community.homey.app/t/how-to-solve-the-error-socket-on-is-not-a-function/121242/7 "2024-11-22T08:44:11Z")

</div>

Thank you~i will have a look.

---

<div class="post-metadata">

**Author:** ![chuck\_rui](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/chuck_rui/32/115662_2.png) [@chuck\_rui](https://community.homey.app/u/chuck_rui)\
**Post date:** [November 22, 2024, 8:57am UTC](https://community.homey.app/t/how-to-solve-the-error-socket-on-is-not-a-function/121242/8 "2024-11-22T08:57:13Z")

</div>

It’s worked out. Thank you very much