function findChild (children, nodeName) {
    for (let k = 0; k < children.length; k++) {
        if (children[k].key === nodeName) {
            return children[k];
        }
    }
}
Return true if both arrays are equal, if both array are null these are considered equal
@method arraysEqual
@memberof utils
@param {Array|null} a1
@param {Array|null} a2
@returns {Boolean}