From afe177cdba8947d997ccd679b8c7951ba161363c Mon Sep 17 00:00:00 2001
From: David Kaltschmidt <david.kaltschmidt@gmail.com>
Date: Mon, 14 Nov 2016 17:16:46 +0100
Subject: [PATCH] Support for feature flags

---
 .../utils/__tests__/feature-utils-test.js     | 30 +++++++++++++++++++
 client/app/scripts/utils/feature-utils.js     | 18 +++++++++++
 client/app/scripts/utils/storage-utils.js     | 25 +++++++++++++++-
 client/package.json                           |  4 +++
 client/test/support/localStorage.js           | 17 +++++++++++
 5 files changed, 93 insertions(+), 1 deletion(-)
 create mode 100644 client/app/scripts/utils/__tests__/feature-utils-test.js
 create mode 100644 client/app/scripts/utils/feature-utils.js
 create mode 100644 client/test/support/localStorage.js

diff --git a/client/app/scripts/utils/__tests__/feature-utils-test.js b/client/app/scripts/utils/__tests__/feature-utils-test.js
new file mode 100644
index 000000000..2395236e4
--- /dev/null
+++ b/client/app/scripts/utils/__tests__/feature-utils-test.js
@@ -0,0 +1,30 @@
+
+const FU = require('../feature-utils');
+
+describe('FeatureUtils', () => {
+  const FEATURE_X_KEY = 'my feature 1';
+  const FEATURE_Y_KEY = 'my feature 2';
+
+  beforeEach(() => {
+    FU.clearFeatures();
+  });
+
+  describe('Setting of features', () => {
+    it('should not have any features by default', () => {
+      expect(FU.featureIsEnabled(FEATURE_X_KEY)).toBeFalsy();
+      expect(FU.featureIsEnabled(FEATURE_Y_KEY)).toBeFalsy();
+    });
+
+    it('should work with enabling one feature', () => {
+      let success;
+      expect(FU.featureIsEnabled(FEATURE_X_KEY)).toBeFalsy();
+      success = FU.setFeature(FEATURE_X_KEY, true);
+      expect(success).toBeTruthy();
+      expect(FU.featureIsEnabled(FEATURE_X_KEY)).toBeTruthy();
+      expect(FU.featureIsEnabled(FEATURE_Y_KEY)).toBeFalsy();
+      success = FU.setFeature(FEATURE_X_KEY, false);
+      expect(success).toBeTruthy();
+      expect(FU.featureIsEnabled(FEATURE_X_KEY)).toBeFalsy();
+    });
+  });
+});
diff --git a/client/app/scripts/utils/feature-utils.js b/client/app/scripts/utils/feature-utils.js
new file mode 100644
index 000000000..abd4ae3b5
--- /dev/null
+++ b/client/app/scripts/utils/feature-utils.js
@@ -0,0 +1,18 @@
+import { storageGetObject, storageSetObject } from './storage-utils';
+
+const STORAGE_FEATURE_KEY = 'scopeFeatureFlags';
+
+export function featureIsEnabled(feature) {
+  const features = storageGetObject(STORAGE_FEATURE_KEY, {});
+  return features[feature];
+}
+
+export function setFeature(feature, isEnabled) {
+  const features = storageGetObject(STORAGE_FEATURE_KEY, {});
+  features[feature] = isEnabled;
+  return storageSetObject(STORAGE_FEATURE_KEY, features);
+}
+
+export function clearFeatures() {
+  return storageSetObject(STORAGE_FEATURE_KEY, {});
+}
diff --git a/client/app/scripts/utils/storage-utils.js b/client/app/scripts/utils/storage-utils.js
index 0ff92ff99..1556fa403 100644
--- a/client/app/scripts/utils/storage-utils.js
+++ b/client/app/scripts/utils/storage-utils.js
@@ -6,7 +6,7 @@ const log = debug('scope:storage-utils');
 const storage = typeof(Storage) !== 'undefined' ? window.localStorage : null;
 
 export function storageGet(key, defaultValue) {
-  if (storage && storage[key] !== undefined) {
+  if (storage && storage.getItem(key) !== undefined) {
     return storage.getItem(key);
   }
   return defaultValue;
@@ -16,8 +16,31 @@ export function storageSet(key, value) {
   if (storage) {
     try {
       storage.setItem(key, value);
+      return true;
     } catch (e) {
       log('Error storing value in storage. Maybe full? Could not store key.', key);
     }
   }
+  return false;
+}
+
+export function storageGetObject(key, defaultValue) {
+  const value = storageGet(key);
+  if (value) {
+    try {
+      return JSON.parse(value);
+    } catch (e) {
+      log('Error getting object for key.', key);
+    }
+  }
+  return defaultValue;
+}
+
+export function storageSetObject(key, obj) {
+  try {
+    return storageSet(key, JSON.stringify(obj));
+  } catch (e) {
+    log('Error encoding object for key', key);
+  }
+  return false;
 }
diff --git a/client/package.json b/client/package.json
index c5505b938..549ff7390 100644
--- a/client/package.json
+++ b/client/package.json
@@ -90,6 +90,10 @@
   },
   "jest": {
     "transform": {".*": "<rootDir>/node_modules/babel-jest"},
+    "scriptPreprocessor": "<rootDir>/node_modules/babel-jest",
+    "setupFiles": [
+      "<rootDir>/test/support/localStorage.js"
+    ],
     "testPathDirs": [
       "<rootDir>/app/scripts"
     ],
diff --git a/client/test/support/localStorage.js b/client/test/support/localStorage.js
new file mode 100644
index 000000000..d153bdf8a
--- /dev/null
+++ b/client/test/support/localStorage.js
@@ -0,0 +1,17 @@
+const localStorageMock = (function() {
+  let store = {};
+  return {
+    store,
+    getItem: function(key) {
+      return store[key];
+    },
+    setItem: function(key, value) {
+      store[key] = value.toString();
+    },
+    clear: function() {
+      store = {};
+    }
+  };
+})();
+Object.defineProperty(window, 'Storage', { value: localStorageMock });
+Object.defineProperty(window, 'localStorage', { value: localStorageMock });