Question

63

How to apply an array of classes to classList.contains?

rated 0 times [ 70] [ 7] / answers: 1 / hits: 15586 / 13 Years ago, fri, june 17, 2011, 12:00:00

In my HTML, I have a div like so:

<div class=a b c></div>

In my JavaScript, I have an array of classes that I'm interested in:

var goodClasses = ['a', 'c'];

In good browsers, I can use the awesome classList feature to test whether or not my div has the appropriate classes:

return div.classList.contains(goodClasses[0], goodClasses[1]);

This is okay, but what I'd really like to do is something like this (the syntax is silly, but this is the general idea):

return div.classList.contains.apply(div, goodClasses);

Is there some way to do this? If I have to loop through my array of classes anyway, classList becomes a whole lot less cool.

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answered 13 Years ago muhammadbrandend · Accepted Answer

As @Felix Kling correctly points out, classList.contains accepts only one argument.

If your supported browsers support the every() method on Array, you could do this:

return goodClasses.every( function( c ) {

    return div.classList.contains( c );

});

Browsers that don't support it can use the MDC compatibility fix:

if (!Array.prototype.every)

{

  Array.prototype.every = function(fun /*, thisp */)

  {

    use strict;



    if (this === void 0 || this === null)

      throw new TypeError();



    var t = Object(this);

    var len = t.length >>> 0;

    if (typeof fun !== function)

      throw new TypeError();



    var thisp = arguments[1];

    for (var i = 0; i < len; i++)

    {

      if (i in t && !fun.call(thisp, t[i], i, t))

        return false;

    }



    return true;

  };

}