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storage.set() not working

I have been trying to add saving to a game I am making. When doing so, I run into a problem

saveGame = function()
  save = object
    playerSave = player1
    enemySave = enemyList
    levelSave = level
    lightSave = lights
    levelNameSave = levelName
    
  end
  
  storage.set("save", save)
end

I called the saveGame() function in the console. I refreshed the game and called storage.get("save"). The console returned an object with only two variables. This was the output:

> storage.get("save")
  object
    playerSave = [object]
    levelNameSave = "level1"
  end

I called the saveGame() function again, but it was the same, even without refreshing the game. I tested the actual save object in the console and got:

> save
  object
    playerSave = [object]
    enemySave = [list]
    levelSave = [object]
    lightSave = [list]
    levelNameSave = "level1"
  end

So my problem is that some of the data in the save object was lost in the console. Please help me, I'm not sure what is happening.

If I follow your steps, I only can see undefined, undefined, undefined...

After seeing your post, I checked the API, I actually found a bug and fixed it. The bug may explain why some of the values you are trying to save aren't actually saving.

The bug was related to the serialization mechanism used for storing objects. When you store a whole object, try to have in mind that your object will be transformed into text (JSON format), with a few side effects:

  • circular structures cannot be saved as such ; if you have a player object which retains a reference to an enemy object, and the enemy itself holds a reference to player, that's a circular reference. The storage API will remove such references in the saved objects.
  • if you have two references to the same object or array before saving them to the storage, once saved and reloaded, they will be recreated as 2 independant copies of the same object.

Example:

enemy = object
  x = 50
  y = 0
end

save = object
  enemy1 = enemy
  enemy2 = enemy
end

if save.enemy1 == save.enemy2 then print("YES") end // => YES, they are equal

storage.set("status",save)

save = storage.get("status")

if save.enemy1 != save.enemy2 then print("NO!") end // => NO, they aren't equal anymore, not the same object, two different copies of the same data

Generally speaking, you should avoid storing your whole structured game data using the storage API as it will certainly lead to many unexpected side effects, due to how serialization works. Instead, you should build a dedicated object which does not hold references to your actual game objects, only to simple numbers or string values. For example:

save = function()
  local obj = object
    position = object
      x = player.x
      y = player.y
    end
    level_num = getLevelNum()
  end

  storage.set("save",obj)
end

load = function()
  local obj = storage.get("save")
  player.x = obj.position.x
  player.y = obj.position.y
  setLevel(obj.level_num)
end

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