How to have function call its own function on its creation

Question

I have a function PublicGame which I'd like to be using similar to a class. When I create PublicGame I give it a bunch of methods by setting this.methodName = function. The only thing is that I want to call some of these methods when the PublicGame is created. Right now for instance I do this.judge = this.setJudge(), but I know this wont work where I have it because, setJudge isnt defined yet. Should I put this at the bottom of PublicGame? Is my design totally off?
Code:

'use strict';
// var GameSockets = require(‘GameSockets’);
var Games = {};
var id_counter = 0;
var minPlayers = 3;
var maxPlayers = 6;
function PublicGame (players) {
 this._id = id_counter++;
 this.players = players;
 this.gameSocket = new GameSockets.registerPlayers(this.players, this._id, this.playerDisconnects);
 this.judge = this.setJudge();
 this.killGame = function() {
 delete Games[this._id];
 };
 // When a player presses leave game
 this.playerExits = function(playerToRemove) {
 // Delete player from players array
 this.players.splice(this.players.indexOf(playerToRemove),1);
 // If less than min players
 if (this.players.length < minPlayers) this.killGame();
 // If less than max players
 if (this.players.length < maxPlayers) {
 this.needsPlayers = true;
 }
 gameSockets.kickPlayer(playerToRemove);
 };
 // When a player disconnects without warning, e.g. closes window
 this.playerDisconnects = function(playerToRemove) {
 // Delete player from players array
 this.players.splice(this.players.indexOf(playerToRemove),1);
 // If less than min players
 if (this.players.length < minPlayers) this.killGame();
 // If less than max players
 if (this.players.length < maxPlayers) {
 this.needsPlayers = true;
 }
 };
 this.selectJudges = function() {
 this.judge = this.players.pop();
 this.players = this.players.unshift(this.judge);
 };
 this.setWinner = function(winner) {
 this.winner = winner;
 };
 Games[this._id] = this;
}

• Anonymous0day: maybe you should read about javascript prototype and inheritance
• MinusFour: I see no setJudge function anywhere.

Answer 1

If you define your functions on the prototype than you do not need to "wait" for the functions to be defined because the instance will already have them when the constructor's code is called

function PublicGame (players) {
 //...
 this.judge = this.setJudge();
}
PublicGame.prototype.killGame = function(){
 //...
};
PublicGame.prototype.playerExits = function(playerToRemove){
 //...
};
PublicGame.prototype.setJudge = function(){
 //do whatever
 return whatever;
};

So unless your functions need to access some "private" variable (ie defined within the constructor, not a global variable), or other reason requiring it, define it on the prototype instead of defining it in the constructor and it will be ready to use.

• Daniel Kobe: So the protoypes would not be able to access anything inside of PublicGame? Would they be able to access players?
• Patrick Evans: They wouldn't be able to access anything defined locally in the constructor, ie like var somevar = 3. You will be able to access players because you have defined it on the instance this.players = players

Answer 2

You have to use javascript prototype !

Read the comments in the code sample.

/*
* utils functions
*
* dont take care about that
**/
var el = document.getElementById('dbg');
var jj = function(val,sep){return JSON.stringify(val , null , sep || '')}
var log = function(val){el.innerHTML+='<div><pre>'+val+'</pre></div>'};
var counterId = 0;
/************************************************************************/
// You have to use prototype
// here an example of what you can achieve
// we create a Player 'class'
var Player = function( name ){ 
 this.id = counterId ++; //<-- an attribute
 this.name = name; //<-- an attribute
 this.setLevel(5);//<-- a method called at 'instanciation'
 
 return this;
};
// a method available at instanciation time
Player.prototype.setLevel = function(level){
 this.level = level;
 return this;
};
// we create a new Player named Toto
var Toto = new Player('Toto');
 log('Toto = ' + jj(Toto));//<-- utility function just to log
// we create a new Player named Jane
var Jane = new Player('Jane');
 log('Jane = ' + jj(Jane)); //<-- utility function just to log
// we change the Level of Jane
Jane.setLevel(12);
log('Jane.setLevel(12)');//<-- utility function just to log
log('Jane = ' + jj(Jane));//<-- utility function just to log

<div id='dbg'></div>

• Patrick Evans: What is this? How does this help OP? It uses nothing of OP's code, and has no explanation to go with it
• Anonymous0day: Sorry but it is in relation with my first comment with OP !