config.rpgsave - how to store data

[Eliaquim]

Hi people!
I'm trying to understand how can I store custom data inside this file.
The reason is that I want a global object to be saved for different save files.
Well, somehow, I managed to do that!
I change the global object in-game and call ConfigManager.save(), then my global object is saved across different save files.

BUT!
The problem is, I can't understand how I do it and why it's working. I've tried to replicate the same pattern that Rpg Maker Mv code does to save the bgmVolume. And somehow managed to work. But I can't really understand why =/

Here is what I have:

ConfigManager.casa = {
    Stage0: null,
    Stage1: [],
    Stage2: [],
    Stage3: [],
    Stage4: [],
    Stage5: [],
    Stage6: []
}

Object.defineProperty(ConfigManager, 'casa', {
    get: function() {
        return casa;
    },
    set: function(value) {
        casa = value;
    },
    configurable: true
});

var _ConfigManager_makeData = ConfigManager.makeData;
ConfigManager.makeData = function() {
    let config = _ConfigManager_makeData.call(this);
    config.casa = this.casa;
    return config;
};

var _ConfigManager_applyData = ConfigManager.applyData;
ConfigManager.applyData = function(config) {
    _ConfigManager_applyData.call(this,config);
    this.casa = this.readCustom(config, 'casa');
};

ConfigManager.readCustom = function(config, name) {
    var value = config[name];
    if (value !== undefined) {
        return config[name];
    } else {
        return {   
            Stage0: null,
            Stage1: [],
            Stage2: [],
            Stage3: [],
            Stage4: [],
            Stage5: [],
            Stage6: []
        };
    }
};

So please, can you try to explain my code to me?

 

[caethyril]

• ConfigManager.makeData creates an object to be saved to the file. It is called by ConfigManager.save:
  
  Spoiler: ConfigManager.save

  // rpg_managers.js
  ConfigManager.save = function() {
      StorageManager.save(-1, JSON.stringify(this.makeData()));
  };

  I.e. "save the makeData result in JSON format to slot -1 (config)". This is needed because you don't want to save all the code associated with the ConfigManager; you only want to save the properties that change.
  
  
• ConfigManager.applyData does the reverse: it sets the ConfigManager properties to the values retrieved from file. It is called by ConfigManager.load:
  
  Spoiler: ConfigManager.load

  // rpg_managers.js
  ConfigManager.load = function() {
      var json;
      var config = {};
      try {
          json = StorageManager.load(-1);
      } catch (e) {
          console.error(e);
      }
      if (json) {
          config = JSON.parse(json);
      }
      this.applyData(config);
  };

  I.e. "load save slot -1 (config), parse that data (string -> object), then apply these values to the ConfigManager".
  
  
• defineProperty just formally defines a property on an object. In case you're interested, you can read up on it here:
  
  

  Object.defineProperty()

  The static method Object.defineProperty() defines a new property directly on an object, or modifies an existing property on an object, and returns the object.

  developer.mozilla.org

 

[Eliaquim]

Thanks @caethyril ! ^^

I think I'm getting it...
So in fact, because of this:

ConfigManager.readCustom = function(config, name) {
    var value = config[name];
    if (value !== undefined) {
        return config[name];
    } else {
        return {   
            Stage0: null,
            Stage1: [],
            Stage2: [],
            Stage3: [],
            Stage4: [],
            Stage5: [],
            Stage6: []
        };
    }
};

I don't need to do this:

ConfigManager.casa = {
    Stage0: null,
    Stage1: [],
    Stage2: [],
    Stage3: [],
    Stage4: [],
    Stage5: [],
    Stage6: []
}

because if ConfigManager.casa is undefined, the ConfigManager.readCustom will set a default value to it. Right?

Reading about the Object.defineProperty...

" just formally defines a property on an object."

So it seems that this can be removed from the code since I can add a new property and a new value to any property like this:
casa.heigth = 100;
?

I guess I will have to learn more about this.
I can't understand why has this "Object.defineProperty", if I can add property and values like above xD
So I guess I'm missing something. But I will keep reading!

 

[caethyril]

...if ConfigManager.casa is undefined, the ConfigManager.readCustom will set a default value to it. Right?

Yes; in that case ConfigManager.casa will be undefined until it loads the settings from file, which happens when Scene_Boot starts. That should be OK, unless you need it to process stuff as soon as the game loads for some reason.

So it seems that this can be removed from the code since I can add a new property and a new value to any property like this:
casa.heigth = 100;
?

I can't understand why has this "Object.defineProperty", if I can add property and values like above xD
So I guess I'm missing something. But I will keep reading!

Yes, in your case it's unnecessary~

Among other things, Object.defineProperty lets you define properties with custom get/set methods. You can make read-only properties, or properties that act as a kind of alias for getting values from elsewhere. For example, ConfigManager.bgmVolume (rpg_managers.js) just points directly to the AudioManager:

Spoiler: ConfigManager.bgmVolume

Object.defineProperty(ConfigManager, 'bgmVolume', {
    get: function() {
        return AudioManager._bgmVolume;
    },
    set: function(value) {
        AudioManager.bgmVolume = value;
    },
    configurable: true
});

Another example is Game_BattlerBase.prototype.mhp (rpg_objects.js): it has a custom "get" method (a.k.a. "getter") so that whenever you ask for a battler's mhp it calls the appropriate function to calculate it, including traits etc.

Spoiler: Game_Battler.prototype.mhp

Object.defineProperties(Game_BattlerBase.prototype, {
// ...
// Maximum Hit Points
    mhp: { get: function() { return this.param(0); }, configurable: true },

 

[Eliaquim]

Thank you @caethyril !
I think I understand that now!

 

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