insertAfter (node, afterNode) {
    if (this._hasChilds()) {
      const index = this.childs.indexOf(afterNode)
      const beforeNode = this.childs[index + 1]
      if (beforeNode) {
        this.insertBefore(node, beforeNode)
      } else {
        this.appendChild(node)
      }
    }
  }
Insert a new child before a given node
Only applicable when Node value is of type array or object
@param {Node} node
@param {Node} afterNode