How to share variables between classes in javascript

Question

I am expanding my JS knowledge by building custom libraries on-top of jQuery/JS and the classes have to interact between each other. I am coming from PHP, so there I could use static variables, but have no idea in JS. Here is an example of what I want:

var A = function() {
    this.myPublicVar = "thisShouldBePrintedFromClassB";
}

A.prototype = {
    showMyVar : function() {alert(this.myPublicVar);} // This gets triggered on direct access.
}

var B = function() {}
B.prototype = {
    // I have no idea how to to access A.myPublicVar
}

Anyone could provide me with simple tutorial or anything?

PS: I have just started to expand my JS knowledge, have used JS/jQuery for easy design purposes (using selectors and building data validators and etc.)

B needs to inherit from A if you want to access that property. — elclanrs
– elclanrs, Commented Apr 5, 2013 at 22:22
B.prototype = new A(); something like this read this it may be useful stackoverflow.com/questions/15843660/… — Givi
– Givi, Commented Apr 5, 2013 at 22:23
and how should I use multiple classes lets say like in a framework(ie. multiple inheritance) — DaGhostman Dimitrov
– DaGhostman Dimitrov, Commented Apr 5, 2013 at 22:25
The problem is that you're thinking in classes. JavaScript prototype model can sort of imitate class inheritance but not the other way around. Think about modules, that's the JavaScript way. — elclanrs
– elclanrs, Commented Apr 5, 2013 at 22:27

Kevin Bowersox · Accepted Answer · 2013-04-05 22:34:27Z

4

You can use inheritance to access the variable.

var A = function() {
    this.myPublicVar = "thisShouldBePrintedFromClassB";
}

A.prototype = {
    showMyVar : function() {alert(this.myPublicVar);} // This gets triggered on direct access.
}

var B = function() {}
B.prototype = new A();
B.prototype.print = function(){
  alert(this.myPublicVar);
}

var b = new B();
b.print();

edited Apr 5, 2013 at 22:34

answered Apr 5, 2013 at 22:24

Kevin Bowersox

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Comments

KingKongFrog · Accepted Answer · 2013-04-05 22:37:02Z

1

var A = function() {
    this.myPublicVar = "thisShouldBePrintedFromClassB";
}

A.prototype = {
    showMyVar : function() {alert(this.myPublicVar);} // This gets triggered on direct access.
}

var B = function() {}
B.prototype = new A();  //This is what you're missing.

console.log(B.prototype.myPublicVar);

edited Apr 5, 2013 at 22:37

answered Apr 5, 2013 at 22:23

KingKongFrog

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