player.js analysis

player-js-analysis.md

1. This file declares a class, Player, instantiates it, and assigns it to a global player variable.

2. The Player class contains four methods:

   • constructor()
   • playPause()
   • skipTo()
   • setVolume()

3. The constructor() method sets initial values for the currentlyPlaying, playState, volume, and soundObject properties.

   • currentlyPlaying is set to the first item in album.songs.
   • The initial playState is "stopped".
   • The volume is set to the number 80.
   • The soundObject instantiates a new buzz.sound object using the soundFileUrl property of this.currentlyPlaying. The buzz variable doesn't appear to be initialized here, so presumably it's a dependency loaded elsewhere.

4. The playPause() method accepts one parameter, song. It sets it to this.currentlyPlaying by default. It checks to see if this.currentlyPlaying is different from song, and if so, it:

   • Stops the soundObject property.
   • Removes the "playing" and "paused" classes from the element property of this.currentlyPlaying.
   • Sets this.currentlyPlaying to the function's parameter, song.
   • Changes the playState property to "stopped".
   • Instantiates a new sound object using this.currentlyPlaying, which was just updated to song.

5. The skipTo() method accepts one parameter, percent. It checks to see if the playState is different from ‘playing’. If it is different, it multiplies the percent of the song, (percent / 100), and the song duration, this.soundObject.getDuration(), and sets the result as the time of the soundObject.

6. The setVolume() method accepts one parameter, percent. This.volume is set to the percent. It then sets the volume to the percent.

7. The getDuration() method returns the duration of the soundObject.

8. The getTime() method returns the time of the soundObject.