Javascript Prototype Programming

Question

I'm trying to include some namespace into my Javascript API.

Here's what I have so far:

if (!Sample || Sample == "undefined")
 var Sample = {};
Sample.SomeApi = {};
Sample.SomeApi.prototype = {
 SomeMethod: function() {
 alert('some api');
 }
};

What's going on here?

When I'm calling Sample.SomeApi.SomeMethod(); // it won't work as it will complain:

Uncaught TypeError: Object #<Object> has no method 'SomeMethod'
(anonymous function)Course:43
onclick

• benastan: Side note: you want undefined or typeof Sample === 'undefined' not "undefined".
• benastan: Well, Sample == "undefined" is not going to test if it is undefined, it is going to test whether Sample equals the string "undefined."
• Luis Perez: Good point, alternatively, he can do Sample == undefined but then again the whole undefined is unnecessary, that's what !Sample is testing for anyway.

Answer 1

I think you meant __proto__ not prototype, like so:

if (!Sample || Sample == "undefined")
 var Sample = {};
Sample.SomeApi = {};
Sample.SomeApi.__proto__ = {
 SomeMethod: function() {
 alert('some api');
 }
};
Sample.SomeApi.SomeMethod();

You can test it out in this jsFiddle: http://jsfiddle.net/luisperezphd/xtyyf/

But why not just this:

if (!Sample || Sample == "undefined")
 var Sample = {};
Sample.SomeApi = {
 SomeMethod: function() {
 alert('some api');
 }
};
Sample.SomeApi.SomeMethod();

It's much cleaner.

And there is the jsFiddle for that: http://jsfiddle.net/luisperezphd/HUuMQ/

• Daff: I'm not so sure about that. That would mean that you assign SomeMethod to the prototype of {}?
• clockworkgeek: Using __proto__ works because objects do not have a prototype, functions do. However __proto__ is not standard and won't work across browsers, that is what getPrototypeOf is for. But the second method really is much cleaner.

Answer 2

You have to create a constructor for Sample.SomeApi not assign an empty object:

if(typeof Sample == 'undefined')
 Sample = {};
Sample.SomeApi = function() {
};
Sample.SomeApi.prototype = {
 someMethod : function() {
 alert('some api');
 }
}
new Sample.SomeApi().someMethod();

• LB.: how would you make it call it like this: Sample.SomeApi.someMethod(); instead of Sample.SomeApi().someMethod(); ?
• Daff: Well you don't need to use the prototype if your API is only a single object. just use Sample.SomeApi = { SomeMethod: function() { alert('some api'); } );

Answer 3

Try this

if(typeof Sample == 'undefined')
 var Sample ={}
 Sample.SomeApi = function(a)
 {
 this.a =a;
 }
Sample.SomeApi.prototype.SomeMethod = function() {
 alert('some api');
 }
 var d = new Sample.SomeApi(1);
 d.SomeMethod();

Hope this helps you

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