You-dont-know-js: Part 3: this & Object Prototypes -> Appendix A: ES6 class -> Class Gotchas

[mzwae]

In the Class Gotchas Section, when I run the code below, I get the following error message:
"Uncaught SyntaxError: 'super' keyword unexpected here"

Why is "super" _not_ expected here?

class P {
foo() { console.log( "P.foo" ); }
}

class C extends P {
foo() {
    super();
}
}

var c1 = new C();
c1.foo(); // "P.foo"

var D = {
foo: function() { console.log( "D.foo" ); }
};

var E = {
foo: C.prototype.foo
};

// Link E to D for delegation
Object.setPrototypeOf( E, D );

E.foo(); // "P.foo"

[zonzujiro]

It's because 'super' - is not a function, but a keyword that helps call methods of object which linked to prototype of the current object.
In this particular case 'super' is used for calling method 'foo' of class P, so it must be super.foo();

You can also call foo function like this: P.prototype.foo.call(this);, but 'super' more beautiful way to do this.

[getify]

super() is only valid in subclass constructors. in methods, must be super.methodName().

[mzwae]

Thank you for your reply.
Is the code below the correct way to use super keyword in the book example?

 class C extends P {
 foo() {
 super.foo();
 }
 }

[getify]

looks ok