How can I fix this error for my discord bot I’m trying to make?

I’m trying to create a discord bot in javascript that plays a specified sound for each specific person that joins the voice channel. Kind of like an intro sound/song thing.

I’m getting this error when I tried to test it out. It outputs this in the terminal when I join the voice channel and the bot doesn’t join the voice channel to play the sound.

PS C:javacodeDiscord Audio Bot> node Audio.js
On
C:javacodeDiscord Audio BotAudio.js:29
  } else if (newState.channel.members.size = 1) {
                              ^

TypeError: Cannot read properties of null (reading 'members')
    at Client.<anonymous> (C:javacodeDiscord Audio BotAudio.js:29:31)
    at Client.emit (node:events:513:28)
    at VoiceStateUpdate.handle (C:javacodeDiscord Audio Botnode_modulesdiscord.jssrcclientactionsVoiceStateUpdate.js:38:14)
    at module.exports [as VOICE_STATE_UPDATE] (C:javacodeDiscord Audio Botnode_modulesdiscord.jssrcclientwebsockethandlersVOICE_STATE_UPDATE.js:4:35)
    at WebSocketManager.handlePacket (C:javacodeDiscord Audio Botnode_modulesdiscord.jssrcclientwebsocketWebSocketManager.js:352:31)
    at WebSocketShard.onPacket (C:javacodeDiscord Audio Botnode_modulesdiscord.jssrcclientwebsocketWebSocketShard.js:489:22)
    at WebSocketShard.onMessage (C:javacodeDiscord Audio Botnode_modulesdiscord.jssrcclientwebsocketWebSocketShard.js:328:10)
    at callListener (C:javacodeDiscord Audio Botnode_moduleswslibevent-target.js:290:14)
    at WebSocket.onMessage (C:javacodeDiscord Audio Botnode_moduleswslibevent-target.js:209:9)
    at WebSocket.emit (node:events:513:28)

This is my code below. Also, how would I go about doing this so that each user has their own different sound?

console.log('On');
const { Client, GatewayIntentBits } = require('discord.js');
const client = new Client({ 
  intents: [
    GatewayIntentBits.GuildVoiceStates,
    GatewayIntentBits.GuildMembers
  ]

});

client.on('voiceStateUpdate', (_oldState, newState) => {
  // Check if the user who joined is the specific user we want
  if (newState.member.id === 'STtheGamer') {
      // Check if the user joined a voice channel
      if (newState.channel) {
          // Join the voice channel and play the specific sound
          newState.channel.join()
              .then(connection => {
                  // Replace 'song.mp3' with the path to the audio file you want to play
                  const dispatcher = connection.play('C:UsersstorrMusicbotsoundsswtheme.mp3');

                  // Leave the voice channel after the sound is played
                  dispatcher.on('finish', () => {
                      newState.channel.leave();
                  });
              })
              .catch(console.error);
      }
  } else if (newState.channel.members.size = 1) {
      if (newState.channel) {
          newState.channel.leave()
              .catch(console.error);
      }
  }

});

  client.login('botkey here');