takePhoto() {    const ctx = wx.createCameraContext()    ctx.takePhoto({      quality: 'high',      success(res) {        console.log('success')        console.log(res)      },      fail(res) {        console.log('takePhoto fail res')        console.log(res)      }        }) [代码]<!-- camera.wxml --> [代码] [代码]<camera device-position="back" flash="off" binderror="error" style="width: 100%; height: 300px;"></camera><button type="primary" bindtap="takePhoto">拍照</button><view>预览</view><image mode="widthFix" src="{{src}}"></image>[代码] Cannot read property 'mode' of undefined;at pages/take_video/video page takePhoto function TypeError: Cannot read property 'mode' of undefined