Tries to define :has-n-children([<|>|<=|>=]n)

slick-has-n-children.js

/* :has-n-children([<|>|<=|>=]n)
 * requires Slick
 * selects elements with (less/more than (or equal to)) n elements as children
 * [2011-07-11] doesn't work yet (tested with 1.1.5)
 * [2016-01-24] works now (testet with 1.6); https://jsfiddle.net/ugLaexhc/2/
 */

Slick.definePseudo('has-n-children', function(arg) {
    var childrenLen = this.children.length;
    var parsedArg = arg.match(/(<|>|<=|>=)?(\d+)/);
    switch(parsedArg[1]) {
        case '<': return childrenLen < parsedArg[2];
        case '<=': return childrenLen <= parsedArg[2];
        case '>': return childrenLen > parsedArg[2];
        case '>=': return childrenLen >= parsedArg[2];
        default: return childrenLen == parsedArg[2];
    }
});