CODEWITHSUNDEEP
javascript
khernik
khernik

Reputation: 2091

Prototype - function not found

I have the following code:

function Tools() { }
Tools.prototype.foobar = function() {
   return 'a';
};

alert(Tools.foobar());

And this code returns an error that the foobar function was not found. Why is that so? It works without the prototype keyword.

Also, what's the difference? As far as I know I can use prototype keyword, and not use it. If it was an object I could understand that it's inheritance, but what about here?

Upvotes: 0

Views: 1675

Answers (1)

rid
rid

Reputation: 63610

You did not set the property foobar on Tools, but instead you set it on Tools.prototype, which means it won't be available on Tools. If you want to call it on Tools, you'd have to set it there:

Tools.foobar = function() { ... };
alert(Tools.foobar());

The purpose of prototype is to specify which properties need to be contained by instances of the function. Therefore, if you want to access these properties, you should create a new instance of the function, with the new keyword.

Tools.prototype.foobar = function() { ... };
var tools = new Tools();
alert(tools.foobar());

Upvotes: 3

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