recursivelyUpdateNodeName () {
    if (this.expanded) {
      this.updateNodeName()
      if (this.childs !== 'undefined') {
        let i
        for (i in this.childs) {
          this.childs[i].recursivelyUpdateNodeName()
        }
      }
    }
  }
update recursively the object's and its children's name.
@private