按两个值按降序对数组中的对象进行排序

Question

I'm dealing with the iTunes API and pulling songs from albums. I'm trying to sort songs in by their track number and according to what disc they belong to but seem to be running into a few issues. For one the order of the discs is in reverse order. Second, its not sorting tracks how they should at all. As a first pass this is how I'm trying to sort things:

return a.discNumber - b.discNumber && a.trackNumber - b.trackNumber;

What needs to fixed in order to get this to work?

 iTunesSearch(); function iTunesSearch(callback) { $.getJSON('http://itunes.apple.com/search?term=Speakerboxxx/The Love Below&entity=song&callback=?', function(data) { var results = data["results"], tracks = results.filter(function(entry) { return entry.collectionExplicitness == "explicit" }), sortedTracks = tracks.sort(function(a,b) { return a.discNumber - b.discNumber && a.trackNumber - b.trackNumber; }); for (var i = 0; i < sortedTracks.length; i++) { var discNo = "<td>" + sortedTracks[i]["discNumber"] + "</td>", trackNo = "<td>" + sortedTracks[i]["trackNumber"] + "</td>", trackName = "<td>" + sortedTracks[i]["trackName"] + "</td>", $tr = "<tr>" + discNo + trackNo + trackName + "</tr>"; $("table").append($tr); } console.log(tracks); }); } 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <table> <thead> <tr> <td>Disc Number</td> <td>Track Number</td> <td>Track Name</td> </tr> </thead> </table> 

Answer 1

You will want to use

return a.discNumber - b.discNumber || a.trackNumber - b.trackNumber;

for your comparison function, so that it does compare the track numbers only when the disc numbers are equal (not the other way round). Then, to sort something descending, just swap a and b :

return a.discNumber - b.discNumber || b.trackNumber - a.trackNumber;

(to get ascending discs, but descending track numbers per disc)

Answer 2

Your comparison only checks the track number if the disc numbers are already different. Not what you want.

Try:

return (a.discNumber - b.discNumber) || (a.trackNumber - b.trackNumber);

 iTunesSearch(); function iTunesSearch(callback) { $.getJSON('http://itunes.apple.com/search?term=Speakerboxxx/The Love Below&entity=song&callback=?', function(data) { var results = data["results"], tracks = results.filter(function(entry) { return entry.collectionExplicitness == "explicit" }), sortedTracks = tracks.sort(function(a,b) { return a.discNumber - b.discNumber || a.trackNumber - b.trackNumber; }); for (var i = 0; i < sortedTracks.length; i++) { var discNo = "<td>" + sortedTracks[i]["discNumber"] + "</td>", trackNo = "<td>" + sortedTracks[i]["trackNumber"] + "</td>", trackName = "<td>" + sortedTracks[i]["trackName"] + "</td>", $tr = "<tr>" + discNo + trackNo + trackName + "</tr>"; $("table").append($tr); } console.log(tracks); }); } 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script> <table> <thead> <tr> <td>Disc Number</td> <td>Track Number</td> <td>Track Name</td> </tr> </thead> </table>