Added the underscore node_module.

node_modules/underscore/modules/_toBufferView.js

@@ -0,0 +1,11 @@
+import getByteLength from './_getByteLength.js';
+
+// Internal function to wrap or shallow-copy an ArrayBuffer,
+// typed array or DataView to a new view, reusing the buffer.
+export default function toBufferView(bufferSource) {
+  return new Uint8Array(
+    bufferSource.buffer || bufferSource,
+    bufferSource.byteOffset || 0,
+    getByteLength(bufferSource)
+  );
+}