Archive for May, 2007

Neat little example of a useful Javascript closure

Sunday, May 6th, 2007

Closures are a powerful feature of JavaScript. However it’s often hard to explain in a few words, just what is useful about closures. Well, here on page 131 of the Rhino book, is the recipe for a unique ID generator that doesn’t require a global counter.

One thing that I personally enjoy about the Flanagan book is that he says things like “don’t pollute the global namespace.” :) This technique does not pollute the global namespace.

var uid = (
function(){
var id=0;
return function(){
return id++ ;
};
}
)();
//then just say:
alert(uid());