Function append

06.Router/basic/js/vue.js:9199–9202

* Append operation that takes a callback. * * @param {Node} el * @param {Node} target * @param {Vue} vm - unused * @param {Function} [cb]

(el, target, vm, cb)

     */

    function append(el, target, vm, cb) {
      target.appendChild(el);
      if (cb) cb();
    }

    /**
     * InsertBefore operation that takes a callback.