Clear hydrated stores (#785)

* Clear hydratedStores on each #react_component call
* Create clearHydratedStores() methods for StoreRegistry.js and ReactOnRails.js
* Add clearHydratedStores() invocation to #initialize_redux_stores helper
* Add JS tests for clearHydratedStores() methods in StoreRegistry.js and ReactOnRails.js
* Remove forgotten console logging
* Update tests and ReactOnRails.js code according to PR review notices
* JS tests now use setStore
* Move clearHydratedStores method to INTERNALLY USED APIs section

app/helpers/react_on_rails_helper.rb

@@ -341,7 +341,11 @@ def initialize_redux_stores
 
     all_stores = (@registered_stores || []) + (@registered_stores_defer_render || [])
 
-    result = all_stores.each_with_object(declarations) do |redux_store_data, memo|
+    result = <<-JS
+      ReactOnRails.clearHydratedStores();
+    JS
+
+    result << all_stores.each_with_object(declarations) do |redux_store_data, memo|
       store_name = redux_store_data[:store_name]
       props = props_string(redux_store_data[:props])
       memo << <<-JS

node_package/src/ReactOnRails.js

@@ -135,6 +135,14 @@ ctx.ReactOnRails = {
     return StoreRegistry.setStore(name, store);
   },
 
+  /**
+   * Clears hydratedStores to avoid accidental usage of wrong store hydrated in previous/parallel
+   * request.
+   */
+  clearHydratedStores() {
+    StoreRegistry.clearHydratedStores();
+  },
+
   /**
    * ReactOnRails.render("HelloWorldApp", {name: "Stranger"}, 'app');
    *

node_package/src/StoreRegistry.js

@@ -81,6 +81,13 @@ This can happen if you are server rendering and either:
     hydratedStores.set(name, store);
   },
 
+  /**
+   * Internally used function to completely clear hydratedStores Map.
+   */
+  clearHydratedStores() {
+    hydratedStores.clear();
+  },
+
   /**
    * Get a Map containing all registered store generators. Useful for debugging.
    * @returns Map where key is the component name and values are the store generators.

node_package/tests/ReactOnRails.test.js

@@ -124,3 +124,24 @@ test('setStore and getStore', (assert) => {
 
   assert.deepEqual(ReactOnRails.stores(), expected);
 });
+
+test('clearHydratedStores', (assert) => {
+  assert.plan(2);
+  function reducer() {
+    return {};
+  }
+
+  function storeGenerator(props) {
+    return createStore(reducer, props);
+  }
+
+  ReactOnRails.setStore('storeGenerator', storeGenerator);
+  const actual = new Map();
+  actual.set(storeGenerator);
+  assert.deepEqual(actual, ReactOnRails.stores());
+
+  ReactOnRails.clearHydratedStores();
+  const expected = new Map();
+  assert.deepEqual(ReactOnRails.stores(), expected,
+    'clearHydratedStores should clear hydratedStores map');
+});

node_package/tests/StoreRegistry.test.js

@@ -87,3 +87,17 @@ test('StoreRegistry throws error for retrieving unregistered hydrated store', (a
     'Expected an exception for calling StoreRegistry.getStore with an invalid name.',
   );
 });
+
+test('StoreRegistry clearHydratedStores', (assert) => {
+  assert.plan(2);
+  StoreRegistry.stores().clear();
+
+  StoreRegistry.setStore('storeGenerator', storeGenerator);
+  const actual = new Map();
+  actual.set(storeGenerator);
+  assert.deepEqual(actual, StoreRegistry.stores());
+
+  StoreRegistry.clearHydratedStores();
+  const expected = new Map();
+  assert.deepEqual(StoreRegistry.stores(), expected);
+});