The documentation for telegraf is here: https://www.npmjs.com/package/telegraf
From what I have read, this should work:
const { Telegraf } = require('telegraf')
const bot = new Telegraf(process.env.BOT_TOKEN)
bot.hears('good morning', (ctx) => ctx.reply('Good morning to you too!'))
bot.launch()
// Enable graceful stop
process.once('SIGINT', () => bot.stop('SIGINT'))
process.once('SIGTERM', () => bot.stop('SIGTERM'))
This is edited code from the first example in the docs.
You can do something like
bot.command(key, (ctx) => {
ctx.reply('A Reply', {
reply_to_message_id: ctx.message.message_id
})
})