Support new reading methods

index.js

@@ -84,6 +84,110 @@ function BlobConstructor(ary, options) {
 };
 
 if (global.Blob) {
+  var stream;
+
+  function promisify(obj) {
+    return new Promise(function(resolve, reject) {
+      obj.onload =
+      obj.onerror = function(evt) {
+        obj.onload =
+        obj.onerror = null;
+
+        evt.type === 'load'
+          ? resolve(obj.result || obj)
+          : reject(new Error('Failed to read the blob/file'));
+      }
+    })
+  }
+
+
+  try {
+    new ReadableStream({ type: 'bytes' });
+    stream = function strea() {
+      var position = 0;
+      var blob = this;
+
+      return new ReadableStream({
+        type: 'bytes',
+        autoAllocateChunkSize: 524288,
+
+        pull: function (controller) {
+          var v = controller.byobRequest.view;
+          var chunk = blob.slice(position, position + v.byteLength);
+          return chunk.arrayBuffer()
+          .then(function (buffer) {
+            var uint8array = new Uint8Array(buffer);
+            var bytesRead = uint8array.byteLength;
+
+            position += bytesRead;
+            v.set(uint8array);
+            controller.byobRequest.respond(bytesRead);
+
+            if (position >= blob.size) {
+              controller.close();
+            }
+          });
+        }
+      });
+    }
+  } catch (e) {
+    try {
+      new ReadableStream({});
+      stream = function stream (blob){
+        var position = 0;
+        var blob = this;
+
+        return new ReadableStream({
+          pull: function (controller) {
+            var chunk = blob.slice(position, position + 524288);
+
+            return chunk.arrayBuffer().then(function (buffer) {
+              position += buffer.byteLength;
+              var uint8array = new Uint8Array(buffer);
+              controller.enqueue(uint8array);
+
+              if (position == blob.size) {
+                controller.close();
+              }
+            });
+          }
+        });
+      }
+    } catch (e) {
+      try {
+        new Response('').body.getReader().read();
+        stream = function stream() {
+          return new Response(this).body;
+        }
+      } catch (e) {
+        stream = function stream() {
+          throw new Error('Include https://github.com/MattiasBuelens/web-streams-polyfill');
+        }
+      }
+    }
+  }
+
+
+  if (!Blob.prototype.arrayBuffer) {
+    Blob.prototype.arrayBuffer = function arrayBuffer() {
+      var fr = new FileReader();
+      fr.readAsArrayBuffer(this);
+      return promisify(fr);
+    }
+  }
+
+  if (!Blob.prototype.text) {
+    Blob.prototype.text = function text() {
+      var fr = new FileReader();
+      fr.readAsText(this);
+      return promisify(fr);
+    }
+  }
+
+  if (!Blob.prototype.stream) {
+    Blob.prototype.stream = stream;
+  }
+
   BlobBuilderConstructor.prototype = Blob.prototype;
   BlobConstructor.prototype = Blob.prototype;
 }