feat(memberships): add memberships adapter interface

src/MembershipsAdapter.js

@@ -0,0 +1,49 @@
+import {throwError} from 'rxjs';
+
+import WebexAdapter from './WebexAdapter';
+
+/**
+ * A Membership object with details about the member.
+ *
+ * @typedef {Object} Membership
+ * @property {string}             ID               The member identifier.
+ * @property {string}             destinationID    ID of the destination for which to get members.
+ * @property {string}             destinationType  type of the membership destination.
+ * @property {Array.<Object>}     members          An array of members information.
+ */
+
+/**
+ * Enum for types of destinations.
+ *
+ * @readonly
+ * @enum {string}
+ */
+export const DestinationType = {
+  ROOM: 'room',
+  MEETING: 'meeting',
+};
+
+/**
+ * This is a base class that defines the interface that maps membership data.
+ * Developers that want to extend `MembershipsAdapter` must implement all of its methods,
+ * adhering to the exact parameters and structure of the returned objects.
+ *
+ * @interface
+ */
+export default class MembershipsAdapter extends WebexAdapter {
+  /**
+   * Returns an observable that emits a Membership object.
+   * Whenever there is an update to the membership, the observable
+   * will emit a new updated Membership object, if datasource permits.
+   *
+   * @param {string} destinationID  ID of the destination for which to get members.
+   * @param {DestinationType} destinationType  type of the membership destination.
+   * @returns {Observable.<Membership>}
+   * @memberof MembershipAdapter
+   */
+  getMembersFromDestination(destinationID, destinationType) {
+    return throwError(
+      new Error('getMembersFromDestination(destinationID, destinationType) must be defined in MembershipsAdapter')
+    );
+  }
+}

src/MembershipsAdapter.test.js

@@ -0,0 +1,33 @@
+import {isObservable} from 'rxjs';
+
+import MembershipsAdapter from './MembershipsAdapter';
+
+describe('Memberships Adapter Interface', () => {
+  let membershipsAdapter;
+
+  beforeEach(() => {
+    membershipsAdapter = new MembershipsAdapter();
+  });
+
+  afterEach(() => {
+    membershipsAdapter = null;
+  });
+
+  describe('getMembership()', () => {
+    test('returns an observable', () => {
+      expect(isObservable(membershipsAdapter.getMembersFromDestination())).toBeTruthy();
+    });
+
+    test('errors because it needs to be defined', (done) => {
+      membershipsAdapter.getMembersFromDestination('meetingID', 'meetingType').subscribe(
+        () => {},
+        (error) => {
+          expect(error.message).toBe(
+            'getMembersFromDestination(destinationID, destinationType) must be defined in MembershipsAdapter'
+          );
+          done();
+        }
+      );
+    });
+  });
+});

src/index.js

@@ -1,5 +1,6 @@
 export {default as WebexAdapter} from './WebexAdapter';
 export {default as ActivitiesAdapter} from './ActivitiesAdapter';
 export {default as MeetingsAdapter, MeetingControlState} from './MeetingsAdapter';
+export {default as MembershipsAdapter, DestinationType} from './MembershipsAdapter';
 export {default as PeopleAdapter, PersonStatus} from './PeopleAdapter';
 export {default as RoomsAdapter, RoomType} from './RoomsAdapter';