Javascript 如何用新的Blob构造函数替换不推荐使用的BLOBuilder？

由于Blobbuilder已被弃用，而且我最近决定使用一种新的面部识别API，所以我很难切换到“blob”

---

但是我一直得到

未捕获的TypeError:Object#在控制台中没有方法“getBlob”

。不知道我错过了什么。如果我尝试使用

bb.append（ab）

I get

Uncaught TypeError:Object在控制台中没有“append”方法。
从
BlobBuilder
切换到
Blob
非常简单。尝试以下向后兼容的代码（catch

块中的内容是您的原始代码）：

---

在使用Blob之前，请先包含这些内容，这样您就可以在只支持已弃用BlobBuilder的浏览器中使用Blob构造函数。

在我的帖子更新中，我尝试了你的代码，收到了“Uncaught TypeError:undefined is not a function”@shayward在我的回答中使用代码，不做任何修改：使用你的原始函数，并用我的代码替换最后几行（

var BlobBuilder……}

）。谢谢，键入：mimeString后出现了一个错误。缺少结束括号。但是对于未来，这也会被删除吗？@shayward中定义了

Blob

构造函数。因此，除非规范再次更改，否则您将是安全的。关于兼容性，请参阅。在本文中添加一些注释可能会有所帮助，以明确每个部分正在做什么。是的，这将使它在将来对其他部分更有帮助。

function dataURItoBlob(dataURI, callback) {
        // convert base64 to raw binary data held in a string
        // doesn't handle URLEncoded DataURIs

        var byteString;
        if (dataURI.split(',')[0].indexOf('base64') >= 0) {
            byteString = atob(dataURI.split(',')[1]);
        } else {
            byteString = unescape(dataURI.split(',')[1]);
        }

        // separate out the mime component
        var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0];

        // write the bytes of the string to an ArrayBuffer
        var ab = new ArrayBuffer(byteString.length);
        var ia = new Uint8Array(ab);
        for (var i = 0; i < byteString.length; i++) {
            ia[i] = byteString.charCodeAt(i);
        }

        // write the ArrayBuffer to a blob, and you're done
        var BlobBuilder = window.WebKitBlobBuilder || window.MozBlobBuilder;
        var bb = new BlobBuilder();
        bb.append(ab);
        return bb.getBlob(mimeString);
}

        // write the ArrayBuffer to a blob, and you're done
        var Blob = window.URL || window.webkitURL;
        var bb = new Blob();

        /*var link = document.createElement('link');
        link.rel = 'stylesheet';
        link.href = window.URL.createObjectURL(blob);
        document.body.appendChild(link);*/

        /*var BlobBuilder = window.WebKitBlobBuilder || window.MozBlobBuilder;
        var bb = new BlobBuilder();
        bb.append(ab);*/
        return bb.getBlob(mimeString);
}

...
    try {
        return new Blob([ab], {type: mimeString});
    } catch (e) {
        // The BlobBuilder API has been deprecated in favour of Blob, but older
        // browsers don't know about the Blob constructor
        // IE10 also supports BlobBuilder, but since the `Blob` constructor
        //  also works, there's no need to add `MSBlobBuilder`.
        var BlobBuilder = window.WebKitBlobBuilder || window.MozBlobBuilder;
        var bb = new BlobBuilder();
        bb.append(ab);
        return bb.getBlob(mimeString);
    }
}

Blob = (function() {
  var nativeBlob = Blob;

  // Add unprefixed slice() method.
  if (Blob.prototype.webkitSlice) {
    Blob.prototype.slice = Blob.prototype.webkitSlice;  
  }
  else if (Blob.prototype.mozSlice) {
    Blob.prototype.slice = Blob.prototype.mozSlice;  
  }

  // Temporarily replace Blob() constructor with one that checks support.
  return function(parts, properties) {
    try {
      // Restore native Blob() constructor, so this check is only evaluated once.
      Blob = nativeBlob;
      return new Blob(parts || [], properties || {});
    }
    catch (e) {
      // If construction fails provide one that uses BlobBuilder.
      Blob = function (parts, properties) {
        var bb = new (WebKitBlobBuilder || MozBlobBuilder), i;
        for (i in parts) {
          bb.append(parts[i]);
        }
        return bb.getBlob(properties && properties.type ? properties.type : undefined);
      };
    }        
  };
}());