1. 新建demo6
<button bindtap="clickBtn" type="primary">
    上传文件
</button>

2. 选择图片
wx.chooseImage({
  success: res =>{
      console.log(res)
  }
})
// tip:其余文件
https://developers.weixin.qq.com/miniprogram/dev/api/media/image/wx.chooseMessageFile.html

3. 拿到临时路径，并上传到云存储
    clickBtn(){
        wx.chooseImage({
          success: res =>{
              var filePath = res.tempFilePaths[0]
              this.cloudFile(filePath)
          }
        })
    },

    cloudFile(path){
        wx.cloud.uploadFile({
            cloudPath: Date.now() + ".jpg",
            filePath: path
        }).then(res =>{
            console.log(res)
        })
    },