From 9d96a8e2f236b94b3549f78dd076430f3525006f Mon Sep 17 00:00:00 2001
From: stevo <stevoland@gmail.com>
Date: Wed, 14 Oct 2015 10:41:35 +0100
Subject: [PATCH] Support fetchDataDeferred

Loads data after route transition on the client
---
 src/containers/Widgets/Widgets.js             |  9 ++-
 .../__tests__/getDataDependencies-test.js     | 78 +++++++++++++++++++
 src/helpers/getDataDependencies.js            | 14 ++--
 src/redux/middleware/transitionMiddleware.js  | 16 ++--
 4 files changed, 102 insertions(+), 15 deletions(-)
 create mode 100644 src/helpers/__tests__/getDataDependencies-test.js

diff --git a/src/containers/Widgets/Widgets.js b/src/containers/Widgets/Widgets.js
index 79484cce8..a6fa0230f 100755
--- a/src/containers/Widgets/Widgets.js
+++ b/src/containers/Widgets/Widgets.js
@@ -26,7 +26,7 @@ class Widgets extends Component {
     editStart: PropTypes.func.isRequired
   }
 
-  static fetchData(getState, dispatch) {
+  static fetchDataDeferred(getState, dispatch) {
     if (!isLoaded(getState())) {
       return dispatch(loadWidgets());
     }
@@ -56,9 +56,10 @@ class Widgets extends Component {
         </h1>
         <DocumentMeta title="React Redux Example: Widgets"/>
         <p>
-          This data was loaded from the server before this route was rendered. If you hit refresh on your browser, the
-          data loading will take place on the server before the page is returned. If you navigated here from another
-          page, the data was fetched from the client.
+          If you hit refresh on your browser, the data loading will take place on the server before the page is returned.
+          If you navigated here from another page, the data was fetched from the client after the route transition.
+          This uses the static method <code>fetchDataDeferred</code>. To block a route transition until some data is loaded, use <code>fetchData</code>.
+          To always render before loading data, even on the server, use <code>componentDidMount</code>.
         </p>
         <p>
           This widgets are stored in your session, so feel free to edit it and refresh.
diff --git a/src/helpers/__tests__/getDataDependencies-test.js b/src/helpers/__tests__/getDataDependencies-test.js
new file mode 100644
index 000000000..08ea664d1
--- /dev/null
+++ b/src/helpers/__tests__/getDataDependencies-test.js
@@ -0,0 +1,78 @@
+import { expect } from 'chai';
+import React from 'react';
+import { div } from 'react-dom';
+import getDataDependencies from '../getDataDependencies';
+
+describe('getDataDependencies', () => {
+  let getState;
+  let dispatch;
+  let location;
+  let params;
+  let CompWithFetchData;
+  let CompWithNoData;
+  let CompWithFetchDataDeferred;
+  let ConnectedCompWithFetchData;
+  let ConnectedCompWithFetchDataDeferred;
+
+  beforeEach(() => {
+    getState = 'getState';
+    dispatch = 'dispatch';
+    location = 'location';
+    params = 'params';
+
+    CompWithNoData = () =>
+      <div />;
+
+    CompWithFetchData = () =>
+      <div />;
+
+    CompWithFetchData.fetchData = (_getState, _dispatch, _location, _params) => {
+      return `fetchData ${_getState} ${_dispatch} ${_location} ${_params}`;
+    };
+    CompWithFetchDataDeferred = () =>
+      <div />;
+
+    CompWithFetchDataDeferred.fetchDataDeferred = (_getState, _dispatch, _location, _params) => {
+      return `fetchDataDeferred ${_getState} ${_dispatch} ${_location} ${_params}`;
+    };
+
+    ConnectedCompWithFetchData = () =>
+      <div/>;
+
+    ConnectedCompWithFetchData.WrappedComponent = CompWithFetchData;
+
+    ConnectedCompWithFetchDataDeferred = () =>
+      <div/>;
+
+    ConnectedCompWithFetchDataDeferred.WrappedComponent = CompWithFetchDataDeferred;
+  });
+
+  it('should get fetchDatas', () => {
+    const deps = getDataDependencies([
+      CompWithFetchData,
+      CompWithNoData,
+      CompWithFetchDataDeferred,
+      ConnectedCompWithFetchData,
+      ConnectedCompWithFetchDataDeferred
+    ], getState, dispatch, location, params);
+
+    expect(deps).to.deep.equal([
+      'fetchData getState dispatch location params',
+      'fetchData getState dispatch location params'
+    ]);
+  });
+
+  it('should get fetchDataDeferreds', () => {
+    const deps = getDataDependencies([
+      CompWithFetchData,
+      CompWithNoData,
+      CompWithFetchDataDeferred,
+      ConnectedCompWithFetchDataDeferred
+    ], getState, dispatch, location, params, true);
+
+    expect(deps).to.deep.equal([
+      'fetchDataDeferred getState dispatch location params',
+      'fetchDataDeferred getState dispatch location params'
+    ]);
+  });
+});
diff --git a/src/helpers/getDataDependencies.js b/src/helpers/getDataDependencies.js
index 5c742fe00..44af9aa7e 100755
--- a/src/helpers/getDataDependencies.js
+++ b/src/helpers/getDataDependencies.js
@@ -1,13 +1,15 @@
-const getDataDependency = (component = {}) => {
+const getDataDependency = (component = {}, methodName) => {
   return component.WrappedComponent ?
-    getDataDependency(component.WrappedComponent) :
-    component.fetchData;
+    getDataDependency(component.WrappedComponent, methodName) :
+    component[methodName];
 };
 
-export default (components, getState, dispatch, location, params) => {
+export default (components, getState, dispatch, location, params, deferred) => {
+  const methodName = deferred ? 'fetchDataDeferred' : 'fetchData';
+
   return components
-    .filter((component) => getDataDependency(component)) // only look at ones with a static fetchData()
-    .map(getDataDependency)                              // pull out fetch data methods
+    .filter((component) => getDataDependency(component, methodName)) // only look at ones with a static fetchData()
+    .map((component) => getDataDependency(component, methodName))    // pull out fetch data methods
     .map(fetchData =>
       fetchData(getState, dispatch, location, params));  // call fetch data methods and save promises
 };
diff --git a/src/redux/middleware/transitionMiddleware.js b/src/redux/middleware/transitionMiddleware.js
index 1707ab76a..c58d7e9da 100644
--- a/src/redux/middleware/transitionMiddleware.js
+++ b/src/redux/middleware/transitionMiddleware.js
@@ -20,11 +20,17 @@ export default ({getState, dispatch}) => next => action => {
       next(action);
     } else {
       const {components, location, params} = action.payload;
-      const promises = getDataDependencies(components, getState, dispatch, location, params);
-      const promise = Promise.all(promises)
-        .then(
-          () => next(action)
-        );
+      const promise = new Promise((resolve) => {
+
+        const doTransition = () => {
+          next(action);
+          Promise.all(getDataDependencies(components, getState, dispatch, location, params, true))
+            .then(resolve, resolve);
+        };
+
+        Promise.all(getDataDependencies(components, getState, dispatch, location, params))
+          .then(doTransition, doTransition);
+      });
 
       if (__SERVER__) {
         // router state is null until ReduxRouter is created so we can use this to store