Not able to get a invite code of discord api

I am making a discord bot which needs to track which user joined the server using which invite link. For that it needs to track discord invite link code generated by the user. Here is my code. I am able to get user id who invited the user, how many users have he already added and the id of the member who joined. What I am not able to get correctly is the invite code. Here is my code

const invites = {} // { guildId: { memberId: count } }
    let Array = [];
    const getInviteCounts = async (guild) => {
      return await new Promise((resolve) => {
        guild.fetchInvites().then((invites) => {
          const inviteCounter = {} // { memberId: count }
  
          invites.forEach((invite) => {
            const { uses, inviter,id } = invite
            const { username, discriminator } = inviter
            console.log("ID is ",invite.code);
            
            const name = `${username}#${discriminator}`
            Array[name] = [inviter,[invite.code]];
            inviteCounter[name] = (inviteCounter[name] || 0) + uses
          })
  
          resolve(inviteCounter)
        })
      })
    }
  
    client.guilds.cache.forEach(async (guild) => {
      invites[guild.id] = await getInviteCounts(guild)
    })
  
    client.on('guildMemberAdd', async (member) => {
      const { guild, id } = member
  
      const invitesBefore = invites[guild.id]
      const invitesAfter = await getInviteCounts(guild)
  
      console.log('BEFORE:', invitesBefore)
      console.log('AFTER:', invitesAfter)
  
      for (const inviter in invitesAfter) {
        if (invitesBefore[inviter] === invitesAfter[inviter] - 1) {
          const channelId = '937987923205304390'
          const channel = guild.channels.cache.get(channelId)
          const count = invitesAfter[inviter]
         let userID =  client.users.cache.find(u => u.tag === inviter).id;
         console.log("USERID",inviter.code); 
         channel.send(
            `Please welcome <@${id}> to the Discord! Invited by ${inviter} (${count} invites)`
          )
            
          invites[guild.id] = invitesAfter
          return
        }
      }
    })