微信小程序页面跳转与返回并回传数据

<view class="flex-wrp">
    <text style="width: 32%;">选择城市</text>
    <input style="width: 68%;" type="text" bindtap="city" placeholder="请选择城市" value="{{cityName}}"/>
   </view>

Page({
 data: {
  cityName:"深圳"  #用来回传的关键字，默认深圳
 },
 city: function(e){
  wx.navigateTo({
    url: '../city/city'
  })
 }

})

cityNameClick: function (event) {
  var cityName = event.currentTarget.dataset.cityname;
  console.log(cityName);

  var pages = getCurrentPages();
  var currPage = pages[pages.length - 1];  //当前页面
  var prevPage = pages[pages.length - 2]; //上一个页面

  //直接调用上一个页面的setData()方法，把数据存到上一个页面中去
  prevPage.setData({
   cityName: cityName
  })

  wx.navigateBack();
 },