Add warning when namespacesRequired is not provided

.eslintrc

@@ -19,6 +19,9 @@
     "react/jsx-filename-extension": 0,
     "react/prefer-stateless-function": 0,
     "no-restricted-syntax": 0,
-    "no-eval": 0
+    "no-eval": 0,
+    "no-console": ["error", {
+      "allow": ["warn", "error"]
+    }]
   }
 }

src/hocs/app-with-translation.js

@@ -67,9 +67,11 @@ export default function (WrappedComponent) {
       }
 
       // Step 2: Determine namespace dependencies
-      let namespacesRequired = config.allLanguages
+      let namespacesRequired = config.ns
       if (Array.isArray(pageProps.namespacesRequired)) {
         ({ namespacesRequired } = pageProps)
+      } else if (process.env.NODE_ENV !== 'production') {
+        console.warn(`You have not declared a namespacesRequired array on your page-level component: ${Component.displayName}. This will cause all namespaces to be sent down to the client, possibly negatively impacting the performance of your app. For more info, see: https://github.com/isaachinman/next-i18next#4-declaring-namespace-dependencies`)
       }
 
       // Step 3: Perform data fetching, depending on environment