send-message.js

async function sendMessage(bot, source, items, formatter, getUrl) {
  const successfullySentIds = []
  for (const item of items) {
    const doSend = async () => {
      await bot.telegram.sendMessage(TELEGRAM_CHANNEL, formatter(source, item), {
        parse_mode: 'markdown',
      })
      successfullySentIds.push(item.id)
    }

    try {
      await doSend()
    } catch (err) {
      if (err.response && err.response.parameters && err.response.parameters.retry_after) {
        const { retry_after } = err.response.parameters
        console.warn(`Telegram warned about rate limits, waiting ${retry_after}s and retrying once`)
        await sleep(retry_after * 1000)
        await doSend()
        continue
      }

      console.error(err)
      throw err
    }
  }

  return successfullySentIds
}