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JavaScript

Posted by Jason Ladieu
Jason Ladieu
10,635 Points

Why use placeholders like 'songs' in the first place? Isn't it much easier to use the name of the variable?

var playList = [
  ['I Did It My Way', 'Frank Sinatra'],
  ['Respect', 'Aretha Franklin'],
  ['Imagin', 'John Lennon'],
  ['Born to Run', 'Bruce Springsteen'],
  ['Louie Louie', 'The Kingsmen'],
  ['Mabellene', 'Chuck Berry']
];

function print(message) {
  document.write(message);
}

function printSongs( songs ) {
  var listHTML = '<ol>';
  for ( var i = 0; i < songs.length; i += 1) {
    listHTML += '<li>' + songs[i][0] + '</li>';
  }
  listHTML += '</ol>';
  print(listHTML);
}

printSongs(playList);

1 Answer

Casey Ydenberg
Casey Ydenberg
15,622 Points

Here, songs exists only within the printSongs function. This makes is really clear that songs is self-contained within that function and could be safely reused on arrays other than playList.

Using the same name within the function as outside of it could be an example of shadowing, which can be confusing. Not defining a songs variable and relying on closure is even worse, since the function is not reusable.

It should be said that these things aren't really an issue in code this simple. But they are examples of good practice that becomes more important in larger scripts/apps.

Jason Ladieu
Jason Ladieu
10,635 Points

OK, that makes a bit more sense. Is there a video on Treehouse that goes over this? I may have watched it already, but I could obviously do with a refresher.

Thanks,

Jason