ES6 (The latest version of JavaScript) now supports classes. Here is a simple example of how to use it with a constructor function.

class Student {
    constructor( { name, age, interestLevel = 5 } = {} ) {
        this.name = name;
        this.age = age;
        this.interestLevel = interestLevel;
        this.grades = new Map();
    }
}
let colper = new Student({ name: 'Colper', age: 32 });

colper.grades.set('JavaScript', 'B');
colper.grades.set('Ruby', 'C');
colper.grades.set('Python', 'D');

console.log(Array.from(colper.grades));