Can you extend a HTMLDivElement in TypeScript?

Question

I am making a DOM based game for the first time. I would like to extend HTMLDivElement, however in TypeScript, HTMLDivElement is an Interface.

I would like to do this p

Answer 1

Also you can 'extend' the HTMLDivElement interface with data members if you wish, not by using extends since it is not a class, but by adding it via the interface. TypeScript interfaces are 'open ended', see page 85 of the spec under 'declaration merging'.

http://www.typescriptlang.org/Content/TypeScript%20Language%20Specification.pdf

for example, the below adds the member 'mydata' of type string to the HTMLDivElement interface.

interface HTMLDivElement {

    mydata : string;

}

// now we can assign a value

 var div = document.getElementById("myDiv"); 

 div.mydata = "test";