.play() and .stop() methods

It would be great if you could paste the whole code but from the top of my head nowPlayingIndex refers to the currently selected song, and when the "next()" function runs in the event of a click on the next button. nowplayingindex increments by one.

Hi Jonathan,

Here's the full code

function Playlist() {
    this.songs = [];
    this.nowPlayingIndex = 0;
}

Playlist.prototype.add = function(song) {
    this.songs.push(song);
};

Playlist.prototype.play = function() {
    var currentSong = this.songs[this.nowPlayingIndex];
    currentSong.play();
};

Playlist.prototype.stop = function(){
    var currentSong = this.songs[this.nowPlayingIndex];
    currentSong.stop();
};

Playlist.prototype.next = function() {
    this.stop();
    this.nowPlayingIndex++;
    if(this.nowPlayingIndex === this.songs.length) {
        this.nowPlayingIndex = 0;
    } else {
    this.play();
    }
};

Ok but I'm a bit confused about this.nowPlayingIndex. If it's set to 0, this means that the first song in the array has this.nowPlayingIndex of 0, and then the second song in the array has this.nowPlayingIndex of 1, song three has this.noPlayingIndex of 2, and so on?

Exactly what you said! :)

ok and the .stop and .play methods, they're native to Javascript? Because I notice that in the .stop and .play prototype definitions, we've not written any code per se that stops or plays the songs. we've just gotten the current song and then added .stop/.play.

If I'm correct they were defined in the beginning in the songs.js file. It made me upset when I realised they were two different functions. but it is because songs is an instance of the Songs constructor which has his own prototypes (stop and play a song)

Ok so .stop and .play have the same definition in songs.js and playlist.js?

If I'm correct Stop and Play in the two files are totally different functions, in order to "work" with functions from different files you need to import them which you will learn in this stage.

the purpose of the stop and play in the song.js will be revealed later on, they will change the class to apply CSS to the song list item to make it appear as if it is playing.

So at this point I don't need to get too worried about how the .stop and .play methods in playlist.js work, because at the moment I don't understand how they do anything.

I wouldn't say this, I'd say you should try to "visualize" what happens in the program as you work through it, and maybe preview changes with console.log and console commands.

I really hope I'm not wrong about the method requiring, I will look into it right now.

I was wrong, the reason the functions are "different" are because they are a prototype function of Songs. and song is an instance of the Songs constructor function. therefore the Songs.prototype.play()/stop() functions will be called only on instances of the Songs constructor function. You defined it in the code as :

var songs = new Songs();

Yeah I understand the .stop and .play methods in the song.js file because they have some definition, i.e. isPlaying = true/false. But in the playlist.js they simply appear as currentSong.stop(); currentSong.play();

Ohhhhhhh

Its because it's inside the play\stop functions accordingly so it can't call the function from inside the same function :]]]]

I'm gonna need to revise that course , thanks Gabriel and goodluck :)

Ok yeah. I'll have to give this time to sink in in my brain. I'm not getting where the definition for .stop() and .play() in playlist.js come from.