super

super([arguments] // calls the parent constructor.
super.functionOnParent([arguments]

class Polygon {
  constructor(height, width) {
    this.name = 'Polygon';
    this.height = height;
    this.width = width;
  }
  sayName() {
    console.log('Hi, I am a ', this.name + '.'
  }
}

class Square extends Polygon {
  constructor(length) {
    this.height; // ReferenceError, super needs to be called first!
    
    // Here, it calls the parent class' constructor with lengths
    // provided for the Polygon's width and height
    super(length, length
    
    // Note: In derived classes, super() must be called before you
    // can use 'this'. Leaving this out will cause a reference error.
    this.name = 'Square';
  }

  get area() {
    return this.height * this.width;
  }

  set area(value) {
    this.height = this.width = Math.sqrt(value
  } 
}

class Human {
  constructor() {}
  static ping() {
    return 'ping';
  }
}

class Computer extends Human {
  constructor() {}
  static pingpong() {
    return super.ping() + ' pong';
  }
}
Computer.pingpong( // 'ping pong'

class Base {
  constructor() {}
  foo() {}
}
class Derived extends Base {
  constructor() {}
  delete() {
    delete super.foo;
  }
}

new Derived().delete( // ReferenceError: invalid delete involving 'super'. 

class X {
  constructor() {
    Object.defineProperty(this, 'prop', {
      configurable: true,
      writable: false, 
      value: 1
    }
  } 
  f() { 
    super.prop = 2;
  }
}

var x = new X(
x.f( // TypeError: "prop" is read-only
console.log(x.prop // 1

var obj1 = {
  method1() {
    console.log('method 1'
  }
}

var obj2 = {
  method2() {
   super.method1(
  }
}

Object.setPrototypeOf(obj2, obj1
obj2.method2( // logs "method 1"