intersection.js

/**
 * Gets the intersection of two arrays
 * @param a An array
 * @param b An array
 * @returns {Array}
 */
function intersection(a, b) {
    b = b.slice();
    var c = [];
    if(a.length > b.length) {
        var t = a; a = b; b = t;
    }
    var l = a.length, l2 = b.length;
    for(var i=0; i<l; i++) {
        var item = a[i];
        for(var j=0; j<l2; j++) {
            var item2 = b[j];
            if(item2 === undefined) continue;
            if(item === item2) {
                b[j] = undefined;
                c.push(item);
                continue;
            }
        }
    }
    return c;
}