Unable to join chat channel - twilio

Question

When trying to join a channel in the twilio code I've been working with, it comes up with the error saying that it "Cannot read property 'getChannelByUniqueName' of null". The chat works but when I try to open it up on a different browser, like firefox instead of chrome, it says the error "Channel with provided unique name already exist". Can anyone help with this problem?
// Initialize the Chat client
chatClient = new Twilio.Chat.Client(data.token);
joinChannels(chatClient);
});
function joinChannels(chatClient) {
chatClient.getSubscribedChannels();
joinChannel('generalss','Generals Chat Channel');
}
function joinChannel(channelName, channelFriendlyName) {
console.log(channelName);
console.log(chatClient);
print('Attempting to join "' + channelName + '" chat channel...');
var promise = chatClient.getChannelByUniqueName(channelName);
promise.then(function(channel) {
console.log('Found ' + channelName + ' channel:');
channels[channelName] = channel;
console.log(channels);
setupChannel();
}).catch(function() {
// If it doesn't exist, let's create it
chatClient.createChannel({
uniqueName: channelName,
friendlyName: channelFriendlyName
}).then(function(channel) {
channels[channelName] = channel;
setupChannel(channelName);
});
});
}

Answer 1

Twilio developer evangelist here.
It looks to me like you aren't passing the chatClient to your joinChannel method (and secondly that the client might not be fully initialised yet).
I would initialise the client with the following, which uses the create method that returns a promise that resolves when the Client is ready.
// Initialize the Chat client
new Twilio.Chat.Client.create(data.token).then(function(chatClient) {
joinChannels(chatClient);
});
});
Then, make sure you pass the client through to the joinChannel method:
function joinChannels(chatClient) {
chatClient.getSubscribedChannels();
joinChannel(chatClient, 'generalss','Generals Chat Channel');
}
function joinChannel(chatClient, channelName, channelFriendlyName) {
// the rest...
}
Let me know if that helps at all.