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OO Javascript Calling method from another method of same object

I'm having trouble calling a method from within another method of the same object.
Any help on what I may be missing, or what to look for, would be greatly appreciated.
var IceCream = function (flavor) {
this.tub = 100;
this.flavor = flavor;
};
IceCream.prototype = {
scoop : function () {
this.updateInventory; alert("scooping");
},
updateInventory : function () {
this.tub --;
alert(this.tub);
}
};
var vanilla = new IceCream("vanilla");
vanilla.scoop();

Convert this
this.updateInventory;
to this
this.updateInventory();
DEMO

AngularJS controller's variable is not updated

I have problem with below code. I have prices factory which returns object containing prices received from server by websocket. Prices are sent after button Create is clicked. Problem is that main.prices variable is not updated at all. I can check everything by Check button, which confirms this. Prices.data is updated, but this.prices is not, but it refers the same object, so I thought it should be updated as well. Do you have any ideas why below does not work as expected?
angular.module('myApp', ['ngWebSocket'])
.factory('ws', ['$websocket', function($websocket){
var url = 'ws://localhost/websocket';
var ws = $websocket(url);
return ws;
}])
.factory('prices', ['ws', function(ws){
var prices = {
data: [],
clear: function(){
this.data = [];
},
create: function(){
ws.send('send')
}
}
ws.onMessage(function(message){
message = JSON.parse(message.data);
var type = message.type;
if (type == 'new prices'){
prices.data = message.data;
}
});
return prices;
}])
.controller('main', ['prices', function(prices){
this.prices = prices.data;
this.check = function(){
console.log('works ', prices.data);
console.log('not works ', this.prices);
};
this.create = function(){
prices.create();
};
this.stop = function(){
prices.clear();
};
}]);
<div ng-controller="main as main">
{{ main.prices }}
<button ng-click="main.create()">Create</button>
<button ng-click="main.stop()">Stop</button>
<button ng-click="main.check()">Check</button>
</div>

There are a lot of issues with the code you posted (working on a fiddle so i can help rework it) ...
First change :
if (type == 'new prices'){
prices.data = message.data;
}
To:
if (type == 'new prices'){
prices.data.length = 0;
prices.data.push.apply(prices.data,message.data) ;//copy all items to the array.
}
From a readability / maintainability point of view you should just use this.prices vs this.prices.data. It's confusing to map them to other variables, when you can just use prices. Also note that I updated it to use "that" constantly to avoid any type of context this issues.
.controller('main', ['prices', function(prices){
var that = this;
that.prices = prices;
that.check = check;
that.create = create;
that.stop = stop;
function check(){
console.log('works ', that.prices.data);
console.log('not works ', that.prices);
}
function create(){
that.prices.create();
}
function stop(){
that.prices.clear();
}
}]);

To add to the previous response, you also have an issue on the clear():
var prices = {
...
clear: function(){
this.data = [];
},
...
}
when you do the clear with this.data = [] you are actually creating a new empty array an storing that in the this.data prop, and since this is a NEW array, the reference on main controller -> this.prices = prices.data; is still pointing to the old one. If you need to delete elements on the array just use this.data.length = 0 as Nix pointed out for the other method. that will keep all references in sync since you are re using the original array

Issue while defining jQuery functions

Trying to define a couple of functions like so:
user = (function() {
var friends_list = (function() {
$.get('/ajax/user/friends_list', function(data) {
......
So I can later on call them when need it like so user.friends_list() but for now, the only thing I get is this following error:
TypeError: Object function () {
var friends_list = (function() {
$.get(....
I just don't know where else to look, any suggestions?

You need to create user as an object, in your case the friends_list is a closure method, it will be availble outside the function
user = {
friends_list : function(){
....
}
}

make a user object and not function
var user = {
friends_list : function(){
$.get('/ajax/user/friends_list', function(data) {
......
}
}
and call it like.. user.friends_list()
fiddle here

You're using a closure here, so friend_list is invisible on the outside of user.
If you want to use closures, to hide some variables, to best way to export friend_list would be:
(function(){
var somePrivateVariable;
window.user = {};
window.user.friend_list = function() {
// make use of somePrivateVariable...
};
})();

user = function() {
this.friends_list = function() {
$.get('/ajax/user/friends_list', function(data) {
......
});
};
return this;
};
Above should also work.
reference http://www.w3schools.com/js/js_objects.asp

You can check out this link
Here is the code:
var global = {};
global.sayHello = function (x){
//do your code here
console.log('Hello ' + x );
};
global.sayHello('Kevin');

user = new function(){
var private_variable;
function private_method(){}
this.global_variable = '';
this.global_method = function(){};
}

How to create a javascript library using a closure

I have written some javascript that I would to encapsulate in a closure so I can use it elsewhere. I would like do do this similar to the way jQuery has done it. I would like to be able to pass in an id to my closure and invoke some functions on it, while setting some options. Similar to this:
<script type="text/javascript">
_snr("#canvas").draw({
imageSrc : someImage.png
});
</script>
I have read a lot of different posts on how to use a closure to do this but am still struggling with the concept. Here is where I left off:
_snr = {};
(function (_snr) {
function merge(root){
for ( var i = 1; i < arguments.length; i++ )
for ( var key in arguments[i] )
root[key] = arguments[i][key];
return root;
}
_snr.draw = function (options) {
var defaults = {
canvasId : 'canvas',
imageSrc : 'images/someimage.png'
}
var options = merge(defaults, options)
return this.each(function() {
//More functions here
});
};
_snr.erase = function () {};
})(_snr);
When ever I try to call the draw function like the first code section above, I get the following error, '_snr is not a function'. Where am I going wrong here?
EDIT
Here is what I ended up doing:
function _snr(id) {
// About object is returned if there is no 'id' parameter
var about = {
Version: 0.2,
Author: "ferics2",
Created: "Summer 2011",
Updated: "3 September 2012"
};
if (id) {
if (window === this) {
return new _snr(id);
}
this.e = document.getElementById(id);
return this;
} else {
// No 'id' parameter was given, return the 'about' object
return about;
}
};
_snr.prototype = (function(){
var merge = function(root) {
for ( var i = 1; i < arguments.length; i++) {
for ( var key in arguments[i] ) {
root[key] = arguments[i][key];
}
}
return root;
};
return {
draw: function(options) {
var defaults = {
canvasId : 'canvas',
imageSrc : 'images/someimage.png'
};
options = merge(defaults, options);
return this;
},
erase: function() {
return this;
}
};
})();
I can now call:
<script type="text/javascript">
_snr("#canvas").draw({
imageSrc : someImage.png
});
</script>

Because you declared _snr as an object and not a function. Functions can have properties and methods, so there's various ways to achieve what you want, for example one of them would be say...
_snr = function(tag) {
this.tag = tag;
}
_snr.foo = function() {
//Code goes here
}
You can also pass the outer context into a closure to hide your variables from accidentally polluting the global namespace, so like...
(function(global) {
var _snr = function(tag) {
this.tag = tag;
}
_snr.foo = function() {
//Code goes here
}
//export the function to the window context:
global._snr = _snr;
})(window);
window._snr('#tag').foo('wat');
Happy coding.

Because your _snr is an object, not a function. You have to call it like this:
_snr.draw({
canvasId: '#canvas',
imageSrc: 'someImage.png'
});

When you do _snr('#canvas') that is a function call which is why you're getting that error. _snr is an object with some methods attached to it such as draw() and erase(). The reason jQuery is able to pass arguments into the $ is because they return the $ as a function object which is why we're able to pass it various selectors as arguments.

You are going wrong at the first line _snr = {}
It needs to be
_snr = function(){
selector = arguments[0]||false;
//snr init on dom object code
return _snrChild;
}
Im on a mobile phone but when im on a pc I will maybe fix the whole code c:

Here you have a snr object and that has erase and draw methods. What you intend to do is to write a _snr function which will get an id and return a wrapper object. That returned object should have erase and draw methods. so you can do
var returnedObject = _snr("my_id");
returnedObject.draw("image.png");

Javascript array is undefined... and I'm not sure why

I'm trying to translate a PHP class into JavaScript. The only thing I'm having trouble with is getting an item out of an array variable. I've created a simple jsfiddle here. I cannot figure out why it won't work.
(EDIT: I updated this code to better reflect what I'm doing. Sorry for the previous mistake.)
function tattooEightBall() {
this.subjects = ['a bear', 'a tiger', 'a sailor'];
this.prediction = make_prediction();
var that = this;
function array_random_pick(somearray) {
//return array[array_rand(array)];
var length = somearray.length;
var random = somearray[Math.floor(Math.random()*somearray.length)];
return random;
}
function make_prediction() {
var prediction = array_random_pick(this.subjects);
return prediction;
}
}
var test = tattooEightBall();
document.write(test.prediction);
​

Works fine here, you are simple not calling
classname();
After you define the function.
Update
When you make a call to *make_prediction* , this will not be in scope. You are right on the money creating a that variable, use it on *make_prediction* :
var that = this;
this.prediction = make_prediction();
function make_prediction() {
var prediction = ''; //initialize it
prediction = prediction + array_random_pick(that.subjects);
return prediction;
}
You can see a working version here: http://jsfiddle.net/zKcpC/
This is actually pretty complex and I believe someone with more experience in Javascript may be able to clarify the situation.
Edit2: Douglas Crockfords explains it with these words:
By convention, we make a private that variable. This is used to make
the object available to the private methods. This is a workaround for
an error in the ECMAScript Language Specification which causes this to
be set incorrectly for inner functions.
To see the complete article head to: http://javascript.crockford.com/private.html

You never call classname. Seems to be working fine.

Works for me:
(function classname() {
this.list = [];
this.list[0] = "tiger";
this.list[1] = "lion";
this.list[2] = "bear";
function pickone(somearray) {
var length = somearray.length;
var random = somearray[Math.floor(Math.random()*length)];
return random;
}
var random_item = pickone(this.list);
document.write(random_item);
}());
Were you actually calling the classname function? Note I wrapped your code block in:
([your_code]());

I'm not sure what you're trying to accomplish exactly with the class structure you were using so I made some guesses, but this code works by creating a classname object that has instance data and a pickone method:
function classname() {
this.list = [];
this.list[0] = "tiger";
this.list[1] = "lion";
this.list[2] = "bear";
this.pickone = function() {
var length = this.list.length;
var random = this.list[Math.floor(Math.random()*length)];
return random;
}
}
var cls = new classname();
var random = cls.pickone();
You can play with it interactively here: http://jsfiddle.net/jfriend00/ReL2h/.

It's working fine for me: http://jsfiddle.net/YznSE/6/ You just didn't call classname(). If you don't call it, nothing will happen ;)

Make it into a self-executing function like this:
(function classname() {
this.list = [];
this.list[0] = "tiger";
this.list[1] = "lion";
this.list[2] = "bear";
function pickone(somearray) {
var length = somearray.length; //<---WHY ISN'T THIS DEFINED??
var random = somearray[Math.floor(Math.random() * length)];
return random;
}
var random_item = pickone(this.list);
document.write(random_item);
})();

var test = tattooEightBall();
document.write(test.prediction);
Should be:
var test = new tattooEightBall(); //forgot new keyword to create object
document.write(test.prediction()); // forgot parens to fire method
and:
this.prediction = make_prediction();
Should be:
this.prediction = make_prediction;