小程序自定义头部，返回按钮，指定返回某页面

 function _navback(backUrl) {
    if(Taro.getCurrentPages().length <=1){
      Taro.switchTab({
            url: "/pages/home/home"
          })
      return
    }

    if(backUrl){
      let Pages = Taro.getCurrentPages(); // 获取当前的页面栈
      let list = [] as any;
      Pages.forEach((item,index)=>{
        if(item.route==backUrl){
          list.push(index)
        }
      })
      if(list.length>1){
        Taro.navigateBack({delta:Pages.length-list[list.length-2]})
      }else {
        Taro.navigateBack()
      }
    return;
    }
    Taro.navigateBack()

  }