Question

I was looking at this code and had a few questions. I did some digging in a jquery fundamentals manual and on google but didn’t find a straightforward answer.

this is the full code

function slideSwitch()
{
    var $active = $('#slideshow IMG.active');

    if ( $active.length == 0 ) $active = $('#slideshow IMG:last');

    var $next =  $active.next().length ? $active.next()
    : $('#slideshow IMG:first');


    $active.addClass('last-active');

    $next.css({opacity: 0.0})
         .addClass('active')
         .animate({opacity: 1.0}, 1000, function() {
             $active.removeClass('active last-active');
          });
}

The first thing that strikes me is that he makes an inline if statement w/o brackets, that’s cool and I didn’t know you could do that. However, is it something that follows good coding standards or does it not matter?

Also the next line where he declares var $next. I’ve never seen a variable with those kinds of conditions in it. I’m guessing that he’s saying either input $active.next() and if the length is 0 than $active.next() is going to be the first img in the slide show. I’m not quite sure what the operands mean.

any insight?

Answer 1

The first thing that strikes me is that he makes an inline if statement w/o brackets

I think you mean braces {}.

that’s cool and I didn’t know you could do that. However, is it something that follows good coding standards or does it not matter?

It is generally considered to be poor code style. It is too easy to come along later to add some more code to an if branch and not realise that the brace-less syntax was used.

JSLint will complain about that.

Also the next line where he declares var $next. I’ve never seen a variable with those kinds of conditions in it.

That’s a conditional (ternary) operator.

return condition ? expr1 : expr2

is equivalent to:

if (condition) {
    return expr1;
} else {
    return expr2;
}

All of this is JavaScript. It has nothing to do with the jQuery library.