Subclass Example

Subclass Example.js

function A () {
    this._v = 1;
    this.bar = function () {
        return this._v;
    }
}

A.prototype.foo = function () {
    return this._v;
};

function B () {
    var internalProto = Object.getPrototypeOf(this);
    var parentInternalProto = Object.getPrototypeOf(internalProto);
    this.parentInternalProto = new (parentInternalProto.constructor);
    Object.setPrototypeOf(internalProto, this.parentInternalProto);
}

Object.setPrototypeOf(B.prototype, A.prototype);

B.prototype.foo = function () {
    return this.parentInternalProto.foo() + this._v;
};

B.prototype.bar = function () {
    return this.parentInternalProto.bar() + this._v;
};

a = new A()
b = new B()

console.log(a.foo(), b.foo())
console.log(a.bar(), b.bar())