js遍歷樹結構並為每個節點設置層級

 setParentId (data, parentId) {
      if (this.pid != parentId) {
        this.level++
      }
      this.pid == parentId
      var num 
      for(var i = 0; i < data.length; i++){
        num = i
        data[i].parentId = parentId
        data[i].level = this.level
        if (data[i].children && data[i].children.length > 0) {
          this.setParentId(data[i].children, data[i].name)
        }
      }
      if (num === data.length - 1) {
        this.level = 2
      }
      return data
}

this.setParentId(this.data)