Step 20.23: Add dataURLToBlob helper

imports/api/images/helpers.js

@@ -0,0 +1,31 @@
+/**
+ * Converts DataURL to Blob object
+ *
+ * https://github.com/ebidel/filer.js/blob/master/src/filer.js#L137
+ *
+ * @param  {String} dataURL
+ * @return {Blob}
+ */
+export function dataURLToBlob(dataURL) {
+    const BASE64_MARKER = ';base64,';
+
+    if (dataURL.indexOf(BASE64_MARKER) === -1) {
+      const parts = dataURL.split(',');
+      const contentType = parts[0].split(':')[1];
+      const raw = decodeURIComponent(parts[1]);
+
+      return new Blob([raw], {type: contentType});
+    }
+
+    const parts = dataURL.split(BASE64_MARKER);
+    const contentType = parts[0].split(':')[1];
+    const raw = window.atob(parts[1]);
+    const rawLength = raw.length;
+    const uInt8Array = new Uint8Array(rawLength);
+
+    for (let i = 0; i < rawLength; ++i) {
+      uInt8Array[i] = raw.charCodeAt(i);
+    }
+
+    return new Blob([uInt8Array], {type: contentType});
+}