example-bot.js

const Telegraf = require('telegraf')
const Extra = require('telegraf/extra')
const session = require('telegraf/session')
const { reply } = Telegraf

const bot = new Telegraf(process.env.BOT_TOKEN)

bot.use(session())

// Register logger middleware
bot.use((ctx, next) => {
  const start = new Date()
  return next().then(() => {
    const ms = new Date() - start
    console.log('response time %sms', ms)
  })
})

const sayYoMiddleware = ({ reply }, next) => reply('yo').then(() => next())

// Random location on some text messages
bot.on('text', ({ replyWithLocation }, next) => {
  if (Math.random() > 0.2) {
    return next()
  }
  return Promise.all([
    replyWithLocation((Math.random() * 180) - 90, (Math.random() * 180) - 90),
    next()
  ])
})

// Text messages handling
bot.hears('Hey', sayYoMiddleware, (ctx) => {
  ctx.session.heyCounter = ctx.session.heyCounter || 0
  ctx.session.heyCounter++
  return ctx.replyWithMarkdown(`_Hey counter:_ ${ctx.session.heyCounter}`)
})

// Command handling
bot.command('answer', sayYoMiddleware, (ctx) => {
  console.log(ctx.message)
  return ctx.reply('*42*', Extra.markdown())
})

const catPhoto = 'http://lorempixel.com/400/200/cats/'
bot.command('cat', ({ replyWithPhoto }) => replyWithPhoto(catPhoto))

// Streaming photo, in case Telegram doesn't accept direct URL
bot.command('cat2', ({ replyWithPhoto }) => replyWithPhoto({ url: catPhoto }))

// Look ma, reply middleware factory
bot.command('foo', reply('http://coub.com/view/9cjmt'))

// Wow! RegEx
bot.hears(/reverse (.+)/, ({ match, reply }) => {
  return reply(match[1].split('').reverse().join(''))
})

// Start polling
bot.startPolling()