From bafe09d820303781d2d507be67983c2747d03ab4 Mon Sep 17 00:00:00 2001
From: Aruna Herath <arunabherath@gmail.com>
Date: Tue, 23 Aug 2016 22:05:00 +0530
Subject: [PATCH] Call 'onStory' only when a story is updated

---
 src/modules/api/configs/__tests__/init_api.js | 12 ++++++++++--
 src/modules/api/configs/init_api.js           |  9 +++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/src/modules/api/configs/__tests__/init_api.js b/src/modules/api/configs/__tests__/init_api.js
index 550977a0985..607fe0755da 100644
--- a/src/modules/api/configs/__tests__/init_api.js
+++ b/src/modules/api/configs/__tests__/init_api.js
@@ -63,10 +63,14 @@ describe('manager.api.config.initApi', () => {
 
   it('should support to add multiple onStory callback', (done) => {
     const actions = { api: {}, shortcuts: {} };
+    const selectedKind = 'XXdd';
+    const selectedStory = 'u8sd';
 
     const reduxStore = {
       subscribe: sinon.stub(),
-      getState: () => ({ api: {} }),
+      getState: () => ({
+        api: { selectedKind, selectedStory },
+      }),
     };
 
     const provider = {
@@ -91,10 +95,14 @@ describe('manager.api.config.initApi', () => {
 
   it('should support a way to remove onStory callback', (done) => {
     const actions = { api: {}, shortcuts: {} };
+    const selectedKind = 'XXdd';
+    const selectedStory = 'u8sd';
 
     const reduxStore = {
       subscribe: sinon.stub(),
-      getState: () => ({ api: {} }),
+      getState: () => ({
+        api: { selectedKind, selectedStory },
+      }),
     };
 
     const provider = {
diff --git a/src/modules/api/configs/init_api.js b/src/modules/api/configs/init_api.js
index 561de344ca3..152bef6542c 100644
--- a/src/modules/api/configs/init_api.js
+++ b/src/modules/api/configs/init_api.js
@@ -29,10 +29,19 @@ export default function (provider, reduxStore, actions) {
   provider.handleAPI(providerApi);
 
   // subscribe to redux store and trigger onStory's callback
+  let currentKind;
+  let currentStory;
   reduxStore.subscribe(function () {
     const { api } = reduxStore.getState();
     if (!api) return;
 
+    if (api.selectedKind === currentKind && api.selectedStory === currentStory) {
+      // No change in the selected story so avoid emitting 'story'
+      return;
+    }
+
+    currentKind = api.selectedKind;
+    currentStory = api.selectedStory;
     callbacks.emit('story', api.selectedKind, api.selectedStory);
     // providerApi._onStoryCallback(api.selectedKind, api.selectedStory);
   });