ES6 classes have inner names

This blog post explains that classes have lexical inner names, just like named function expressions.

The inner names of function expressions  #

You may know that function expressions have lexical inner names:

const fac = function me(n) {
    if (n > 0) {
        // Use inner name `me` to
        // refer to function
        return n * me(n-1);
    } else {
        return 1;
    }
};
console.log(fac(3)); // 6

The name me of the named function expression becomes a lexically bound variable that is unaffected by which variable currently holds the function.

The inner names of classes  #

Interestingly, ES6 classes also have lexical inner names that you can use in methods (constructor methods and regular methods):

class C {
    constructor() {
        // Use inner name C to refer to class
        console.log(`constructor: ${C.prop}`);
    }
    logProp() {
        // Use inner name C to refer to class
        console.log(`logProp: ${C.prop}`);
    }
}
C.prop = 'Hi!';

const D = C;
C = null;

// C is not a class, anymore:
new C().logProp();
    // TypeError: C is not a function

// But inside the class, the identifier C
// still works
new D().logProp();
    // constructor: Hi!
    // logProp: Hi!

(In the ES6 spec the inner name is set up by the dynamic semantics of ClassDefinitionEvaluation.)

Acknowledgement: Thanks to Michael Ficarra for pointing out that classes have inner names.