How to change Class's Prototype in ES6

Question

Following is my Class, Its prototype vale is not getting changed, (I am working on the Chrome console)

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

    getArea() {
        return this.length * this.width;
    }

    static create(length, width) {
        return new Rectangle(length, width);
    }
}

and I am Changing the prototype of the Class to null

Rectangle.prototype= null

When I try to access the changed Prototype, the value remains the same "Object" with 'getArea' prototype property of Rectangle

But in ES5 the prototype value is changed.

Answer 1

In ES6, the .prototype property of classes is not writable and not configurable¹. Use strict mode where you do the assignment and you'll get ReferenceError exception "Invalid assignment in strict mode".

If you want to overwrite the .prototype (which is a very bad idea in general), you'll have to use Object.defineProperty(Rectangle, "prototype", {value: …}).

_{1: See §14.5.14 ClassDefinitionEvaluation, step 16: Perform MakeConstructor(F, writablePrototype=false, prototype=proto).}