Merge pull request #30 from percy/fetch

Allow 10 seconds for stories to be set on window.
percy · Mar 12, 2018 · bf1d5df · bf1d5df
2 parents 02d6498 + f3eb31c
commit bf1d5df
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Showing 2 changed files with 34 additions and 7 deletions.
diff --git a/packages/percy-storybook/src/__tests__/getStories-tests.js b/packages/percy-storybook/src/__tests__/getStories-tests.js
@@ -1,6 +1,17 @@
 import getStories from '../getStories';
 import { storiesKey } from '../constants';
 
+let originalTimeout = 0;
+
+beforeEach(function() {
+  originalTimeout = jasmine.DEFAULT_TIMEOUT_INTERVAL;
+  jasmine.DEFAULT_TIMEOUT_INTERVAL = 12000;
+});
+
+afterEach(function() {
+  jasmine.DEFAULT_TIMEOUT_INTERVAL = originalTimeout;
+});
+
 it('raises an error when called with an empty object', async () => {
   try {
     await getStories();

diff --git a/packages/percy-storybook/src/getStories.js b/packages/percy-storybook/src/getStories.js
@@ -61,13 +61,29 @@ function getStoriesFromDom(previewJavascriptCode, options) {
       src: [workerMock, localStorageMock, matchMediaMock, previewJavascriptCode],
       done: (err, window) => {
         if (err) return reject(err.response.body);
-        if (!window || !window[storiesKey]) {
-          const message =
-            'Storybook object not found on window. ' +
-            "Check your call to serializeStories in your Storybook's config.js.";
-          reject(new Error(message));
-        }
-        resolve(window[storiesKey]);
+        if (!window) return reject(new Error('Window not found when looking for stories.'));
+
+        // Check if the window has stories every 100ms for up to 10 seconds.
+        // This allows 10 seconds for any async pre-tasks (like fetch) to complete.
+        // Usually stories will be found on the first loop.
+        var checkStories = function(timesCalled) {
+          if (window[storiesKey]) {
+            // Found the stories, return them.
+            resolve(window[storiesKey]);
+          } else if (timesCalled < 100) {
+            // Stories not found yet, try again 100ms from now
+            setTimeout(() => {
+              checkStories(timesCalled + 1);
+            }, 100);
+          } else {
+            // Attempted 100 times, give up.
+            const message =
+              'Storybook object not found on window. ' +
+              "Check your call to serializeStories in your Storybook's config.js.";
+            reject(new Error(message));
+          }
+        };
+        checkStories(0);
       },
     };
     if (options.debug) {