minio临时凭证 下载大文件合并UInt8Arrays

// 获取 minioClient
    getMinioClient(tempuser){
      this.minioClient = new Minio.Client({
        endPoint: '172.16.1.16',
        port: 9000,
        useSSL: false,
        region: 'kyc',
        accessKey: tempuser.accessKey,
        secretKey: tempuser.secretKey,
        sessionToken: tempuser.sessionToken,
      });
    },

handleMinio() {
      let size = 0
      let _this = this;
      let url = [{src: ""},{src: ""},{src: ""},{src: ""},{src: ""},{src: ""}];
      let images = ["images/1.jpg", "images/2.jpg", "images/3.jpg", "images/4.jpg", "images/5.jpg", "images/6.jpg"];
      
      for (let i = 0; i < images.length; i++) {
         loadNext(i);
      }
      async function loadNext(e) {
          //获取文件
          let chunks = [];
            await new Promise((resolve, reject) => {
              _this.minioClient.getObject('kyc', images[e], function(err, dataStream) {
                if (err) {
                  return console.log(err)
                }
                dataStream.on('data', function(chunk) {
                  size += chunk.length;
                  chunks = mergeTypedArrays(chunks, chunk); 
                })
                dataStream.on('end', function() {
                  console.log('End. Total size = ' + size)
                  // 保存文件
                  // saveFile(e+".jpg", "image/jpeg", chunks);

                  // 转b64encoded图片
                  var b64encoded = btoa(String.fromCharCode.apply(null, chunks));
                  let src = 'data:image/jpeg;base64,' + b64encoded;
                  url[e].src = src;
                })
                dataStream.on('error', function(err) {
                  console.log(err)
                })
              })
          });
      }
      this.imgurl = url;
      
      function mergeTypedArrays(a, b) {
        if(!a && !b) throw '请为a和b指定有效参数。';  
        if(!b || b.length === 0) return a;
        if(!a || a.length === 0) return b;
        // 确保两个类型化数组的类型相同
        if(Object.prototype.toString.call(a) !== Object.prototype.toString.call(b)) throw 'a和b参数类型不匹配。';
        var c = new a.constructor(a.length + b.length);
        c.set(a);
        c.set(b, a.length);

        return c;
      }
    },

/**
 * 下载数据文件文件
 * @param {String} path - 文件地址
 * @param {String} name - 文件名,eg: test.png
 */
 export const saveFile = (name, type, data) => {
    if (data !== null && navigator.msSaveBlob) {
      return navigator.msSaveBlob(new Blob([data], { type: type }), name);
    }
    var a = document.createElement('a');
    a.style.display = "none";
    var url = window.URL.createObjectURL(new Blob([data], {type: type}));
    a.setAttribute("href", url);
    a.setAttribute("download", name);
    document.body.appendChild(a);
    a.click();
    window.URL.revokeObjectURL(url);
    a.remove();
}