Throw when routes are empty or malformed

src/store-enhancer.js

@@ -28,6 +28,11 @@ import { default as matcherFactory } from './create-matcher';
 import routerReducer from './reducer';
 import initialRouterState from './initial-router-state';
 
+const README_MESSAGE = `
+  See the README for more information:
+  https://github.com/FormidableLabs/redux-little-router#wiring-up-the-boilerplate
+`;
+
 type LocationDidChangeArgs = {
   location: Location,
   matchRoute: Function
@@ -86,6 +91,26 @@ export default ({
   createMatcher = matcherFactory,
   history: userHistory
 }: StoreEnhancerArgs) => {
+  if (!routes) {
+    throw Error(`
+      Missing route configuration. You must define your routes as
+      an object where the keys are routes and the values are any
+      route-specific data.
+
+      ${README_MESSAGE}
+    `);
+  }
+
+  // eslint-disable-next-line no-magic-numbers
+  if (!Object.keys(routes).every(route => route.indexOf('/') === 0)) {
+    throw Error(`
+      The route configuration you provided is malformed. Make sure
+      that all of your routes start with a slash.
+
+      ${README_MESSAGE}
+    `);
+  }
+
   const history = userHistory || resolveHistory({
     basename, forServerRender
   });

test/store-enhancer.spec.js

@@ -15,7 +15,7 @@ import createStoreWithRouter, {
   initializeCurrentLocation
 } from '../src/store-enhancer';
 
-import routes from './fixtures/routes';
+import defaultRoutes from './fixtures/routes';
 
 chai.use(sinonChai);
 
@@ -34,6 +34,7 @@ const defaultFakeInitialState = {
 
 const fakeStore = ({
   initialState = defaultFakeInitialState,
+  routes = defaultRoutes,
   useHistoryStub = true,
   isLoop = false,
   enhancerOptions = {}
@@ -81,6 +82,22 @@ const fakeStore = ({
 };
 
 describe('Router store enhancer', () => {
+  it('throws if no routes are provided', () => {
+    expect(() => fakeStore({
+      routes: null
+    })).to.throw(Error);
+  });
+
+  it('throws if malformed routes are provided', () => {
+    expect(() => fakeStore({
+      routes: {
+        'jlshdkfjgh': {},
+        '/real-route': {},
+        'w': 'tf'
+      }
+    })).to.throw(Error);
+  });
+
   it('updates the pathname in the state tree after dispatching history actions', done => {
     const { store } = fakeStore();