Tmi.js in node.js question

Chat and IRC
3

Checking locally whatever you already are in the channel or not is probably the cleanest way to go about it.

// untested..
client.on("chat", function (channel, userstate, message, self) {

    // Don't listen to my own messages..
    if (self) return;

	// ... logics
	
	const target = '#' + userstate.username;

	if(!client.getChannels().includes(target)){
		// target is not in the channel list
		client.join(target)
	}
    
});

You could also consider throttling / rate limiting the function if someone is abusing it (google it).