bind绑定方法

class 类上的方法

class TvControl {
  constructor() {
    this._nextId = 1
    this.root = new TvNode(this)
    this.multiSelectAble = false
    this.onNodeCreate = null  //默认为null
  }
    get focusNode() {
    let len = this.selectedNodes.length
    return len ? this.selectedNodes[len - 1] : null
   }
  }

页面绑定方法时：

    async initCtrls() {
      let self = this
      self.vItem.multiSelectAble = true
      self.vItem.onNodeCreate = self.onItemNodeCreate()//错误方法
      self.vItem.onNodeCreate = self.onItemNodeCreate.bind(self) //正确方法
      }
    },

执行时：

//类上的方法
  addChild(title, data, params = null) {
    let child = this._createNode(title, data, params)
    let allowCreate = this.vControl.isNodeNeedAllowCreate && this.vControl.onNodeAllowCreate ? this.vControl.onNodeAllowCreate(child) : true
    if (!allowCreate) return null

    this.children.push(child)
    if (this.vControl.onNodeCreate) {
      this.vControl.onNodeCreate(child, params)//传参
    }
    return child
  }

例子：

执行时