Edit in JSFiddle

class Auto {
    constructor(data) {
        this.make = data.make;
        this.model = data.model;
        this.year = data.year;
        this.price = data.price;
    }

    getDetails() {
        return `${this.year} ${this.make} ${this.model}`;
    }
}

class Car extends Auto {
    constructor(data) {
        super(data);
        this.isElectric = data.isElectric;
        this.isHatchback = data.isHatchback;
    }

    getDetails() {
        return `${super.getDetails()} Electric: ${this.isElectric} Hatchback: ${this.isHatchback}`;
    }
}

var car = new Car({
   make: 'Chevy',
   model: 'Malibu',
   price: 30000, 
   year: 2014,
   isElectric: false,
   isHatchback: false
});

var div = document.getElementById('output');
div.innerHTML = car.getDetails();

<h1>Using ES6 Classes</h1>
<div id="output"></div>