DiscordCLI - the beginning to discord cli edition... jk.. idk tho.. who knows tbh..

README

Make sure you call DiscordCLI after you set your listeners, but before you login!

DiscordCLI.js

const readline = require("readline");

class DiscordCLI {
    constructor(client, options){
        this.channel = null;
        this.client = client;
        this.options = {
            exit_message: "EXIT_CHANNEL",
            prompt_format: "#:channel [You] > ",
            incoming_format: "#:channel [:sender] > :message"
        };
        this.options = Object.assign({}, this.options, options);

        this.init();
    }

    init(){
        this.client.on("message", message => {
            if(message.channel.id !== this.channel.id) return;
            if(message.author.id === this.client.user.id) return;
            console.log(this.options.incoming_format.replace(":channel", message.channel.name).replace(":sender", message.author.username).replace(":message", message.content));
        });

        this.rl = readline.createInterface({
            input: process.stdin,
            output: process.stdout
        });

        this.client.on("ready", () => {this.askFor("channel")});
    }

    askFor(what){
        switch(what.toLowerCase()){
            case "channel":
                this.rl.question("Channel Id: ", id => {
                    id = id.trim();
                    this.channel = this.client.channels.get(id);
                    if(this.channel != null){
                        console.log("Channel found and set.");
                        console.log("You are now sending messages to #"+this.channel.name+" in "+this.channel.guild.name);
                        console.log("To leave send '"+this.options.exit_message+"'.");
                        this.askFor("message");
                    }else{
                        console.log("Channel not found!");
                        this.askFor("channel");
                    }
                });
                break;

            case "message":
                let message_prompt = this.options.prompt_format.replace(":guild", this.channel.guild.name).replace(":channel", this.channel.name);
                this.rl.question(message_prompt, input => {
                    if(input === this.options.exit_message){
                        this.channel = null;
                        this.askFor("channel");
                        return;
                    }
                    this.channel.send(input);
                    this.askFor("message");
                });
                break;
        }
    }
}

module.exports = DiscordCLI;

ExampleBot.js

const discord = require("discord.js"),
      client = new discord.Client();
const DiscordCLI = require("./DiscordCLI");

client.on("ready", () => {
  console.log("Bot is ready!");
});

new DiscordCLI(client, {
  exit_message: "leave"
});

client.login("<your token>");