jQuery Extension: removeClassExcept() method

I came across a question on StackOverflow.com where the user wanted the ability to remove all classes from an element except certain ones.  For example if I had the following element

<div class="aa bb cc dd ee">Lorem Ipsum</div>

How would you go about removing all classes except for “aa” and “bb”?  One way would be to just set the class attribute to the classes you wanted to keep.


$("div").attr("class", "aa bb");

That’s easy enough.  Another way would be to use some built in jQuery methods.


$("div").removeClass().addClass("aa bb");

The previous code would remove all classes and then add back the ones that were needed.  That snippet could be put into a jQuery extension to make it easier to call.


jQuery.fn.removeClassExcept = function (val) {
    return this.each(function () {
        $(this).removeClass().addClass(val);
    });
};

$("div").removeClassExcept("aa bb");

That makes the code look cleaner.  One problem both of these solutions have is they don’t check to see if the class already exists before adding it.  On the Stack Overflow question, Brad Christie proposed a solution to handle the case where you didn’t want to add a class unless it already existed.  The updated extension now takes that into consideration.


jQuery.fn.removeClassExcept = function (val) {
    return this.each(function (index, el) {
        var keep = val.split(" "),  // list we'd like to keep
            reAdd = [],          // ones that should be re-added if found
            $el = $(el);       // element we're working on

        // look for which we re-add (based on them already existing)
        for (var i = 0; i < keep.length; i++){
            if ($el.hasClass(keep[i])) reAdd.push(keep[i]);
         }

         // drop all, and only add those confirmed as existing
         $el
            .removeClass()               // remove existing classes
            .addClass(reAdd.join(' '));  // re-add the confirmed ones
    });
};

Here is a jsFiddle showing the use of removeClassExcept(): http://jsfiddle.net/9xhND/1/

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jQuery Extension: removeClassExcept() method

jQuery Extension: toggleText() method

Skip straight to the demo.

Here’s a situation I have run into multiple times: I have a hidden area that is toggled by a link.  The link will usually say “Show *”, and once it is clicked it will say “Hide *”.  I would usually just check the text when the link is clicked and switch it.  Similar to the following:

$("a").click(function() {
    var $self = $(this);
    if ($self.text() == "Show items")
       $self.text("Hide items");
    else
        $self.text("Show items");
});

It would get tedious to add this to every link that toggled the view on an element.  In order to make it easier on myself I threw together a little extension for jQuery.  You pass it 2 string values representing the text that you would like to toggle.  Here is an example usage that does the same thing as the code block above:

$("a").click(function() {
    $(this).toggleText("Show", "Hide");
});

The extension looks for the first value in the element’s text and if it exists, it is replaced with the second value.  If the first value doesn’t exist in the element’s text, it looks for the second value in the text and replaces it with the first value.   Here is the source:

jQuery.fn.toggleText = function (value1, value2) {
    return this.each(function () {
        var $this = $(this),
            text = $this.text();

        if (text.indexOf(value1) > -1)
            $this.text(text.replace(value1, value2));
        else
            $this.text(text.replace(value2, value1));
    });
};

To see it in action, you can view the demo.

jQuery Extension: toggleText() method