> On 23.12.2010 18:28, Joel Dart wrote:
> new is a bad part primarily because of its dangerous potential for adding
> global variables.
> Specifically, using the previous example
>
> > function A(x) {
> > this.x = x;
> > }
>
> > A.prototype.foo = function () {
> > return this.x;
> > };
>
> > // and instance of the constructor "A"
> > var a = new A(10);
>
> If instead you accidentally forgot new:
>
> var a = A(10);
>
> A would be a normal function call and, inside A, “this” would point to the
> global object. You’d create a new global variable x which is obviously
> unintended. Using the Object.create pattern you have a consistent experience
> and don’t have to validate if you and your coworkers properly used “new.”
Or simply do this in your constructors and it becomes an irrelevant
point:
function Point(x, y){
if(!(this instanceof Point)
return new Point(x, y);
this.x = x;
this.y = y;
}
Plus when using the constructor pattern, Java style "super" calls can
be emulated with apply()
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