Updated the files.

my-app/node_modules/symbol-observable/es/index.js

@@ -0,0 +1,19 @@
+/* global window */
+import ponyfill from './ponyfill.js';
+
+var root;
+
+if (typeof self !== 'undefined') {
+  root = self;
+} else if (typeof window !== 'undefined') {
+  root = window;
+} else if (typeof global !== 'undefined') {
+  root = global;
+} else if (typeof module !== 'undefined') {
+  root = module;
+} else {
+  root = Function('return this')();
+}
+
+var result = ponyfill(root);
+export default result;

my-app/node_modules/symbol-observable/es/ponyfill.js

@@ -0,0 +1,34 @@
+export default function symbolObservablePonyfill(root) {
+	var result;
+	var Symbol = root.Symbol;
+
+	if (typeof Symbol === 'function') {
+		if (Symbol.observable) {
+			result = Symbol.observable;
+		} else {
+
+			if (typeof Symbol.for === 'function') {
+				// This just needs to be something that won't trample other user's Symbol.for use
+				// It also will guide people to the source of their issues, if this is problematic.
+				// META: It's a resource locator!
+				result = Symbol.for('https://github.com/benlesh/symbol-observable');
+			} else {
+				// Symbol.for didn't exist! The best we can do at this point is a totally 
+				// unique symbol. Note that the string argument here is a descriptor, not
+				// an identifier. This symbol is unique.
+				result = Symbol('https://github.com/benlesh/symbol-observable');
+			}
+			try {
+				Symbol.observable = result;
+			} catch (err) {
+				// Do nothing. In some environments, users have frozen `Symbol` for security reasons,
+				// if it is frozen assigning to it will throw. In this case, we don't care, because
+				// they will need to use the returned value from the ponyfill.
+			}
+		}
+	} else {
+		result = '@@observable';
+	}
+
+	return result;
+};