Adding Command To Menu and making it do something.

I goto select my new command for bestiary, but it won't do anything except freeze game even though i have common event set
to do something. Heres the code:

/*:
*
*@author ApocalympseGaming1992
*@plugindesc
*This is a custom menu for my game Dungeon Dweller.
*
*@help
*=======GUIDE:=======
*Goto the Common Events Page and add a PluginCommand for "EnemyBook open".(NO QUOTES OR PERIOD.)
*
*@param commandName
*@desc Name of command thats shows up on Menu.
*@default Bestiary
*
*/

var cmd = String(PluginManager.parameters('AG1992_D_D_Menu')['commandName']);
var transparent = 0;
(function(){

Window_MenuCommand.prototype.makeCommandList = function() {
this.addMainCommands();
this.addFormationCommand();
this.addOriginalCommands();
this.addOptionsCommand();
this.addSaveCommand();
this.addGameEndCommand();
};

Window_MenuCommand.prototype.addMainCommands = function() {
var enabled = this.areMainCommandsEnabled();
if (this.needsCommand('item')) {
this.addCommand(TextManager.item, 'item', enabled);
}
if (this.needsCommand('skill')) {
this.addCommand(TextManager.skill, 'skill', enabled);
}
if (this.needsCommand('equip')) {
this.addCommand(TextManager.equip, 'equip', enabled);
}
if (this.needsCommand('status')) {
this.addCommand(TextManager.status, 'status', enabled);
}
if (this.needsCommand('bestiary')) {
this.addCommand(cmd, 'bestiary', enabled);
}
};

Scene_Menu.prototype.createCommandWindow = function() {
this._commandWindow = new Window_MenuCommand(0, 0);
this._commandWindow.setHandler('item', this.commandItem.bind(this));
this._commandWindow.setHandler('skill', this.commandPersonal.bind(this));
this._commandWindow.setHandler('equip', this.commandPersonal.bind(this));
this._commandWindow.setHandler('status', this.commandPersonal.bind(this));
this._commandWindow.setHandler('formation', this.commandFormation.bind(this));
this._commandWindow.setHandler('options', this.commandOptions.bind(this));
this._commandWindow.setHandler('save', this.commandSave.bind(this));
this._commandWindow.setHandler('bestiary', this.commandBestiary.bind(this));
this._commandWindow.setHandler('gameEnd', this.commandGameEnd.bind(this));
this._commandWindow.setHandler('cancel', this.popScene.bind(this));
this.addWindow(this._commandWindow);
};

Scene_Menu.prototype.commandBestiary = function(){
$gameTemp.reserveCommonEvent(1);
};
})();

Well, your code shoud be polished a little:

Code:

(function(){
// I suggest to insert all your methods inside the scope.

var parameters = PluginManager.parameters('AG1992_D_D_Menu') //Set the object parameters inside a variable. This way is easier to use for all the parameters you want.
var cmd = String(parameters['commandName']); //Call your parameters
var transparent = 0;

// No need of recalling the making of the command list, because you didn't make any edit to it.

//When you want to edit and old method, remember to ALIAS it. In js when you write a method with //the same name of the old one, it will be REPLACED. So, making an alias preserves all the contents //of the other methods and assure compatibility with other possible plugins.

var oldWindowMenuCommandAddMainCommands = Window_MenuCommand.prototype.addMainCommands
Window_MenuCommand.prototype.addMainCommands = function() {
oldWindowMenuCommandAddMainCommands.call(this)
this.addCommand(cmd, 'bestiary');
};

//Same Here

var oldCreateCommandWindow = Scene_Menu.prototype.createCommandWindow
Scene_Menu.prototype.createCommandWindow = function() {
oldCreateCommandWindow.call(this) //Calls the alias;
this._commandWindow.setHandler('bestiary', this.commandBestiary.bind(this));
};

// I'm not really sure about this approach, but if you want to load a common event that is processed on map, we can try to do this
Scene_Menu.prototype.commandBestiary = function(){
$gameTemp.reserveCommonEvent(1);
this.popScene() //Returns the map and processses the common event.
};
})();

Remember that is really important to alias methods which have importants information.