How to get and save photo by group media in telegrafjs

trackImages.ts

import { Composer, MiddlewareFn } from "telegraf"

import { logAction } from "app/core/helpers/logAction"
import { BotContext } from "types"
import { report } from "../helpers"
import { withoutKeys } from "app/core/helpers/misc"
import { Message } from "typegram"

// @see https://github.com/TGxTG/TOUGAO/blob/master/src/model/Message.js#L86

const map = new Map()

const trackImages: MiddlewareFn<BotContext> = Composer.on("photo", async (ctx, next) => {
  logAction("trackImages")

  try {
    const { message } = ctx

    if (message.media_group_id) {
      let groupMsg = processMediaMessage(message)
      const handler = setTimeout(() => ctx.reply(groupMsg), 500)

      clearTimeout(handler)

      let reply_to_message_id = message.message_id
        ? message.message_id
        : groupMsg.media[0].message_id

      ctx.replyWithMediaGroup(groupMsg.media, {
        reply_to_message_id,
      })

      logAction("medias map", JSON.stringify(groupMsg))
    } else {
      ctx.reply(`MSG w/o GroupMedia: ${JSON.stringify({ message })}`)
      logAction("medias map", JSON.stringify(message))
    }
  } catch (error) {
    report(error, "trackImages")
  } finally {
    return next()
  }
})

function processMediaMessage(message: Message.PhotoMessage) {
  logAction("processMediaMessage")

  try {
    const mediaId = message.media_group_id
    let groupMsg = map.get(mediaId)

    if (!groupMsg) {
      groupMsg = withoutKeys(message, ["caption", "photo", "video", "message_id"])
      groupMsg.media = []
    } else {
      let ids = Object.keys(groupMsg.media).map((f) => groupMsg.media[f].message_id)
      if (ids.includes(message.message_id)) {
        return groupMsg
      }
    }

    const photo = message.photo.pop()
    const mediaRow: Record<string, any> = {
      message_id: message.message_id,
      media: photo?.file_id,
      type: "photo",
      size: {
        weigth: photo?.file_size,
        height: 320,
        width: 254,
      },
      parse_mode: "Markdown",
    }

    if (message.caption) {
      mediaRow.caption = message.caption
    }

    groupMsg.media.push(mediaRow)

    if (groupMsg.media[0].caption) {
      groupMsg.caption = groupMsg.media[0].caption
    }

    // add / update
    map.set(mediaId, groupMsg)

    logAction("count media ==>", groupMsg.media.length)

    return map.get(mediaId)
  } catch (error) {
    report(error, "processMediaMessage")
  }
}

export default trackImages