wxmini/custom-tab-bar/tabbar.js

const eventBus = {
  // 存储所有事件和对应的订阅者
  eventList: new Map(),
  // 订阅事件
  on(event, callback) {
    if (!this.eventList.has(event)) {
      this.eventList.set(event, new Set())
    }
    this.eventList.get(event).add(callback)
  },
  // 取消订阅事件
  off(event, callback) {
    if (this.eventList.has(event)) {
      const callbacks = this.eventList.get(event)
      callbacks.delete(callback)
      if (callbacks.size === 0) {
        this.eventList.delete(event)
      }
    }
  },
  // 发布事件
  emit(event, ...args) {
    if (this.eventList.has(event)) {
      const callbacks = this.eventList.get(event)
      callbacks.forEach((callback) => {
        callback.call(null, ...args)
      })
    }
  }
}

function selectIndex(index) {
  var pages = getCurrentPages();
  var curPage = pages[pages.length - 1]
  if (typeof curPage.getTabBar === 'function' &&
    curPage.getTabBar()) {
    curPage.getTabBar().setData({
      selected: index
    })
  }
}

function eventOn(curPage) {
  getApp().eventBus.on('rightChange', data => {
    // var pages = getCurrentPages();
    // var curPage = pages[pages.length - 1]
    if (data !== curPage.data.rightId) {
      curPage.setData({
        rightId: data
      })
      if (curPage.data.rightId === 2) {
        let num = curPage.data.rightId === 1 ? 2 : 1
        if (typeof curPage.getTabBar === 'function' &&
          curPage.getTabBar()) {
          curPage.getTabBar().setData({
            selected: num
          })
        }
      }
    }
  });
}

module.exports = {
  eventBus,
  selectIndex,
  eventOn
}