feat(ActivityJson): implement the adapter

Author: akoushke

src/adapters/ActivitiesJSONAdapter.js

@@ -0,0 +1,48 @@
+import {Observable} from 'rxjs';
+
+import ActivitiesAdapter from './ActivitiesAdapter';
+
+/**
+ * @typedef ActivitiesJSON
+ * @param {object} datasource An object that contains a set of activities keyed by ID.
+ * @example
+ * {
+ *   "activity-1": {
+ *     "ID": "activity-1",
+ *     "roomID": "roomID",
+ *     "text": "text",
+ *     "personID": "personID",
+ *     "created": "created",
+ *     "displayAuthor": false
+ *    }
+ * }
+ */
+
+/*
+ * Implements the ActivitiesAdapter interface with a JSON object as its datasource. See @ActivitiesJSON
+ */
+export default class ActivitiesJSONAdapter extends ActivitiesAdapter {
+  constructor(datasource) {
+    super(datasource);
+    this.getActivity = this.getActivity.bind(this);
+  }
+
+  /**
+   * Returns an observable that emits activity data of the given ID.
+   *
+   * @param {string} ID ID of activity to get
+   * @returns {Observable.<Activity>}
+   * @memberof ActivityJSONAdapter
+   */
+  getActivity(ID) {
+    return Observable.create((observer) => {
+      if (this.datasource[ID]) {
+        observer.next(this.datasource[ID]);
+      } else {
+        observer.error(new Error(`Could not find activity with ID "${ID}"`));
+      }
+
+      observer.complete();
+    });
+  }
+}

src/adapters/ActivitiesJSONAdapter.test.js

@@ -0,0 +1,50 @@
+import activities from './../data/activities';
+import ActivitiesJSONAdapter from './ActivitiesJSONAdapter';
+
+describe('Activities JSON Adapter Interface', () => {
+  let activitiesJSONAdapter, activityID;
+
+  beforeEach(() => {
+    [activityID] = Object.keys(activities);
+    activitiesJSONAdapter = new ActivitiesJSONAdapter(activities);
+  });
+
+  test('getActivity() returns an observable', () => {
+    expect(rxjs.isObservable(activitiesJSONAdapter.getActivity())).toBeTruthy();
+  });
+
+  test('getActivity() returns an activity', (done) => {
+    activitiesJSONAdapter.getActivity(activityID).subscribe((data) => {
+      expect(data).toEqual(activities[activityID]);
+      done();
+    });
+  });
+
+  test(`getActivity() throws a proper error message when activity doesn't exist`, (done) => {
+    const wrongActivityID = 'wrongActivityID';
+
+    activitiesJSONAdapter.getActivity(wrongActivityID).subscribe(
+      () => {},
+      (error) => {
+        expect(error.message).toBe(`Could not find activity with ID "${wrongActivityID}"`);
+        done();
+      }
+    );
+  });
+
+  test('getActivity() completes the observable', (done) => {
+    activitiesJSONAdapter.getActivity(activityID).subscribe(
+      () => {},
+      () => {},
+      () => {
+        expect(true).toBeTruthy();
+        done();
+      }
+    );
+  });
+
+  afterEach(() => {
+    activityID = null;
+    activitiesJSONAdapter = null;
+  });
+});

src/adapters/index.js

@@ -1,3 +1,5 @@
 export {default as WebexAdapter} from './WebexAdapter';
 export {default as PeopleAdapter} from './PeopleAdapter';
 export {default as PeopleJSONAdapter} from './PeopleJSONAdapter';
+export {default as ActivitiesAdapter} from './ActivitiesAdapter';
+export {default as ActivitiesJSONAdapter} from './ActivitiesJSONAdapter';

src/data/activities.json

@@ -0,0 +1,10 @@
+{
+  "activity-1": {
+    "ID": "activity-1",
+    "roomID": "roomID",
+    "text": "text",
+    "personID": "personID",
+    "created": "created",
+    "displayAuthor": false
+  }
+}