七牛JSSDK-获取图片的原始宽高

BeforeUpload: (up, file) => {
              // 每个文件上传前,处理相关的事情
                let nativeFile = file.getNative() // 获取file的源文件信息
                let img = new Image()
                img.src = URL.createObjectURL(nativeFile)
                img.onload = function() {
                  let width = img.naturalWidth,
                  height = img.naturalHeight
                  console.log(width,height)
                }
              }
            }