图片地址 转为 blob 、base64格式

//imgurl 图片url
   export function getBase64ByURL (imgUrl) {
    return new Promise(resolve => {
      window.URL = window.URL || window.webkitURL;
      var xhr = new XMLHttpRequest();
      xhr.open("get", imgUrl, true);
      xhr.responseType = "blob";
      xhr.onload = function () {
        if (this.status == 200) {
          var blob = this.response;
          let oFileReader = new FileReader();
          oFileReader.onloadend = function (e) {
            resolve({blob,base64:e.target.result})
          };
          oFileReader.readAsDataURL(blob);
        }
      };
      xhr.send();
    })
  },
//============
// 调用
  getBase64ByURL(url).then(res=>{
      let {blob,base64} = res
      console.log(blob,base64,"blob,base64")
  })