wx.enableAlertBeforeUnload (opens new window)

在onShow里开启即可

wx.enableAlertBeforeUnload({
      message: 'Are you sure you want to leave?',
      success(res) {
        console.log('success:', res)
      },
      fail(res) {
        console.log('fail:', res)
      },
      complete(res) {
        console.log('complete:', res)
      }
    })