access static functions with this

Question

If I have a class:

class Rectangle {
  constructor(height, width) {
    this.height = height;
    this.width = width;
  }

  getArea() {
    return Rectangle.area(this.height, this.width);
  }

  static area(height, width) {
    return height * width;
  }
}

Then I can make an instance of that class and call my getArea function on the instance:

var x = new Rectangle(5,6);
console.log(x.getArea());

Now, say for some reason in my getArea function, instead of calling Rectangle.area directly, I wanted to find the class dynamically and call the static method on whatever dynamically the class instance is:

  getArea() {
    return this.class.area(this.height, this.width);
  }

In PHP, I can do that by something like static::area() or self::area(). How can I do something similar to static and self in Javascript to dynamically access static methods from the class that this belongs to?

did you tried it with just `return this.area(this.height, this.width);` — bill.gates, Aug 05 '20 at 12:22
you can create a property in constructor which refer to its __proto__ chain to access it. All static property or method stored in constructor property: create a property in constructor " this.self = this.__proto__.constructor" Now self variable has access of all the static method and property. getArea() { return this.self.area(this.height,this.width) } — deepak, Aug 05 '20 at 12:32
@deepak Why all that bending over backwards when `this.constructor.area(..)` will do?! — deceze, Aug 05 '20 at 12:35
@deceze - surely it will work , I just want to make clear how object store static data. — deepak, Aug 05 '20 at 12:38

score 1 · Accepted Answer · answered Aug 05 '20 at 12:12

1

You can refer to x.constructor.area(). When an instance is created, its constructor property will be made to refer to the constructor function. That's where static methods are found.

answered Aug 05 '20 at 12:12

Pointy

405,095
59
585
614

Thanks for your answer. I made [this jsfiddle](https://jsfiddle.net/gqcxLok7/) to test how `this.constructor` works when you extend a class. – TKoL Aug 05 '20 at 13:18

access static functions with this

1 Answers1