PRDV401: Introduction to JavaScript I

The super keyword can be used in two ways: as a "function call" (super(...args)), or as a "property lookup" (super.prop and super[expr]).

const child = {
  myParent() {
    console.log(super); // SyntaxError: 'super' keyword unexpected here
  },
};

In the constructor body of a derived class (with extends), the super keyword may appear as a "function call" (super(...args)), which must be called before the this keyword is used, and before the constructor returns. It calls the parent class's constructor and binds the parent class's public fields, after which the derived class's constructor can further access and modify this.

The "property lookup" form can be used to access methods and properties of an object literal's or class's [[Prototype]]. Within a class's body, the reference of super can be either the superclass's constructor itself, or the constructor's prototype, depending on whether the execution context is instance creation or class initialization. See the Examples section for more details.

Note that the reference of super is determined by the class or object literal super was declared in, not the object the method is called on. Therefore, unbinding or re-binding a method doesn't change the reference of super in it (although they do change the reference of this). You can see super as a variable in the class or object literal scope, which the methods create a closure over. (But also beware that it's not actually not a variable, as explained above).

When setting properties through super, the property is set on this instead.