let rewardedVideoAd = null
Page({
  onLoad() {
    if(wx.createRewardedVideoAd){
      rewardedVideoAd = wx.createRewardedVideoAd({ adUnitId: 'xxxx' })
      rewardedVideoAd.onLoad(() => {
        console.log('onLoad event emit')
      })
      rewardedVideoAd.onError((err) => {
        console.log('onError event emit', err)
      })
      rewardedVideoAd.onClose((res) => {
        console.log('onClose event emit', res)
      })
    }
  }
})

rewardedVideoAd.onLoad(() => {
  console.log('Rewarded video ad loaded successfully')
})

rewardedVideoAd.show()
.then(() => console.log('Rewarded video ad displayed'))

rewardedVideoAd.onError(err => {  console.log(err)})

rewardedVideoAd.onClose(res => {
    // The user tapped the close button.
    if (res && res.isEnded) {
      // Normal playback ended, reward can be issued
    } else {
      // Playback was interrupted, no reward issued
    }
})