bot.js

const Telegraf = require('telegraf');   // Module to use Telegraf API.
const {Extra, Markup} = Telegraf;   // Extract Extra, Markups from Telegraf module.
const config = require('./config'); // Configuration file that holds telegraf_token API key.

const bot = new Telegraf(config.telegraf_token);    // Let's instantiate a bot using our token.

// We can get bot nickname from bot informations. This is particularly useful for groups.
bot.telegram.getMe().then((bot_informations) => {
    bot.options.username = bot_informations.username;
    console.log("Server has initialized bot nickname. Nick: "+bot_informations.username);
});

// Command example, pretty easy. Each callback passes as parameter the context.
// Context data includes message info, timestamp, etc; check the official documentation or print ctx.
bot.command('start', (ctx) => ctx.reply('Bot started.'));

// Hears, instead of command, check if the given word or regexp is CONTAINED in user input and not necessarly at beginning.
bot.hears('ymca', (ctx) => ctx.reply("*sing* It's fun to stay at the Y.M.C.A.!"));
bot.hears(/torino/i, (ctx) => ctx.reply("Someone said Torino!?"));

// Inline query support (@yourbot query). Can be used anywhere, even in groups. It works just like @gif bot.
bot.on('inline_query', ctx => {
    let query = ctx.update.inline_query.query;  // If you analyze the context structure, query field contains our query.
    if(query.startsWith("/")){  // If user input is @yourbot /command
        if(query.startsWith("/audio_src")){ // If user input is @yourbot /audio_src
            // In this case we answer with a list of ogg voice data.
            // It will be shown as a tooltip. You can add more than 1 element in this JSON array. Check API usage "InlineResultVoice".
            return ctx.answerInlineQuery([
                {
                    type: 'voice',  // It's a voice file.
                    id: ctx.update.inline_query.id,    // We reflect the same ID of the request back.
                    title: 'Send audio file sample.ogg',    // Message appearing in tooltip.
                    voice_url: 'https://upload.wikimedia.org/wikipedia/commons/c/c8/Example.ogg',
                    voice_duration: 16, // We can specify optionally the length in seconds.
                    caption: '[BOT] Audio file sample.ogg!' // What appears after you send voice file.
                }
            ]);
        }
    }else{  // If user input is @yourbot name
        let name_target = query;    // Let's assume the query is actually the name.
        let message_length = name_target.length;    // Name length. We want to ensure it's > 0.
        if(message_length > 0){
            let full_message;
            let dice=Math.floor(Math.random()*8)+1; // Let's throw a dice for a random message. (1, 8)
            switch(dice){
                case 1: full_message = "IMHO, "+name_target+" sucks."; break;
                case 2: full_message = "IMHO, "+name_target+" is awesome"; break;
                case 3: full_message = name_target+" is not a nice people for me..."; break;
                case 4: full_message = name_target+" for me you are c- Eh! You wanted!"; break;
                case 5: full_message = "Whoa! "+name_target+" is very cool!"; break;
                case 6: full_message = "Grifondoro! No wait, "+name_target+" you're such a noob."; break;
                case 7: full_message = "Sometimes I ask myself why people like "+name_target+" dress up and walk around like that..."; break;
                case 8: full_message = "Watch him! Watch! "+name_target+" is so ugly!"; break;
            }
            // Let's return a single tooltip, not cached (In order to always change random value).
            return ctx.answerInlineQuery([{
                type: 'article',
                id: ctx.update.inline_query.id, 
                title: 'You have inserted: '+name_target, 
                description: 'What does '+bot.options.username+' thinks about '+name_target+'?',
                input_message_content: {message_text: full_message}
            }], {cache_time: 0});
        }
    }
})

// Start bot polling in order to not terminate Node.js application.
bot.startPolling();