[util] Add base64toBlob function

src/jio.js

@@ -165,27 +165,32 @@
   }
   util.stringify = stringify;
 
+  function base64toBlob(b64String, mimeString) {
 
-  // https://gist.github.com/davoclavo/4424731
-  function dataURItoBlob(dataURI) {
-    if (dataURI === 'data:') {
-      return new Blob();
-    }
-    // convert base64 to raw binary data held in a string
-    var byteString = atob(dataURI.split(',')[1]),
-    // separate out the mime component
-      mimeString = dataURI.split(',')[0].split(':')[1],
+    var byteString = atob(b64String),
     // write the bytes of the string to an ArrayBuffer
       arrayBuffer = new ArrayBuffer(byteString.length),
       _ia = new Uint8Array(arrayBuffer),
       i;
-    mimeString = mimeString.slice(0, mimeString.length - ";base64".length);
     for (i = 0; i < byteString.length; i += 1) {
       _ia[i] = byteString.charCodeAt(i);
     }
     return new Blob([arrayBuffer], {type: mimeString});
   }
 
+  util.base64toBlob = base64toBlob;
+
+  // https://gist.github.com/davoclavo/4424731
+  function dataURItoBlob(dataURI) {
+    if (dataURI === 'data:') {
+      return new Blob();
+    }
+    // convert base64 to raw binary data held in a string
+    var mimeString = dataURI.split(',')[0].split(':')[1];
+    mimeString = mimeString.slice(0, mimeString.length - ";base64".length);
+    return base64toBlob(dataURI.split(',')[1], mimeString);
+  }
+
   util.dataURItoBlob = dataURItoBlob;
 
   // tools