gistfile1.js

class Media {
  constructor(title, duration, isPlaying = false) {
    this.title = title;
    this.duration = duration;
    this.isPlaying = isPlaying; 
  }
  
  start() {
    this.isPlaying = true;
  }
  
  stop() {
    this.isPlaying = false;
  }
}

class Song extends Media {
  constructor(title, artist, duration, isPlaying = false) {
    super(title, duration, isPlaying);
    this.artist = artist;
  } 

  toString() {
  	return `<li>
          ${this.title} - ${this.artist} <span>${this.duration}</span>
        </li>`;
  }

}