ApendTable.lua

local nk = require("nakama")

local function AppendTable(context, payload)

  local user_id = "removed-for-sharing-on-gist" -- some user ID.
  
  local json = nk.json_decode(payload)
  local listWrapper = nk.json_decode(json.value)

  local object_ids = {
    {collection = json.collection, key = json.key, user_id = user_id}
  }

  local objects = nk.storage_read(object_ids)


  for _, r in ipairs(objects)
  do
    local storagaTable = nk.json_decode(r.value).List
    
    for _, v in iparis(storagaTable)
    do
      table.insert(listWrapper.List, v)
    end
    
    local new_objects = {
      {collection = json.collection, key = json.key, user_id = user_id, value = nk.json_encode(listWrapper), permission_read = 2, permission_write = 1}
    }
    nk.storage_write(new_objects)
    return "Appended"
  end
  return "Failed to append. Payload: " .. nk.json_encode(value) .. "   On Storage: " .. nk.json_encode(r.value)
end

nk.register_rpc(AppendTable, "append_object")