fix fetching after enroll (#3808)

* make data optional as it's already skipped in some events
* add spec for re-fetch behavior

tutor/specs/components/my-courses.spec.jsx

@@ -39,6 +39,18 @@ describe('My Courses Component', function() {
         expect.snapshot(<C><CourseListing /></C>).toMatchSnapshot();
     });
 
+    it('re-fetches courses if the back button is used', () => {
+        currentCourses.fetch = jest.fn(() => Promise.resolve());
+
+        let wrapper = mount(<C><CourseListing /></C>);
+        expect(currentCourses.fetch).not.toHaveBeenCalled();
+        wrapper.unmount();
+
+        wrapper = mount(<C><CourseListing history={{ action: 'POP' }} /></C>);
+        expect(currentCourses.fetch).toHaveBeenCalled();
+        wrapper.unmount();
+    });
+
     it('renders the listing sorted', function() {
         const wrapper = mount(<C><CourseListing /></C>);
         for (let i = 0; i < MASTER_COURSES_LIST.length; i++) {

tutor/specs/models/user.spec.ts

@@ -30,7 +30,7 @@ describe('User Model', () => {
         expect(User.metrics.course_subjects).toEqual('testing');
         expect(User.metrics.course_types).toEqual('real');
     })
-  
+
     it('calculates audience tags', () => {
         bootstrapCoursesList();
         expect(User.tourAudienceTags).toEqual(['teacher', 'teacher-not-previewed']);
@@ -105,6 +105,11 @@ describe('User Model', () => {
         expect(JSON.parse(body)).toMatchObject({
             some: 'data',
         })
+
+        // Some events do not contain data
+        fetchMock.mockResponseOnce(JSON.stringify({ ok: true }))
+        User.logEvent({ category: 'nodata', code: 'nodata' })
+        expect(fetchMock.mock.calls[1][1]?.body).toBeUndefined()
     }))
 
     it('checks for names then splits', action(() => {

tutor/src/components/my-courses/index.jsx → tutor/src/components/my-courses/index.tsx

@@ -9,16 +9,24 @@ import TourRegion from '../tours/region';
 import PendingVerification from './pending-verification';
 import NonAllowedTeacher from './non-allowed-teacher';
 import { MyCoursesPast, MyCoursesCurrent } from './listings';
+import { RouteComponentProps } from 'react-router-dom'
+
+interface MyCoursesProps {
+    history?: RouteComponentProps['history']
+}
 
 @observer
-export default
-class MyCourses extends React.Component {
-    constructor(props) {
+class MyCourses extends React.Component<MyCoursesProps> {
+    constructor(props: MyCoursesProps) {
         super(props);
         modelize(this);
     }
 
-    componentDidMount() {
+    async componentDidMount() {
+        const { history } = this.props;
+        if (history && history.action === 'POP') {
+            await currentCourses.fetch();
+        }
         currentUser.logEvent({ category: 'onboarding', code: 'arrived_my_courses' });
     }
 
@@ -27,7 +35,7 @@ class MyCourses extends React.Component {
     }
 
     @computed get shouldRedirect() {
-        if (currentCourses.size !== 1){
+        if (currentCourses.size !== 1) {
             return false;
         }
         return (
@@ -72,8 +80,10 @@ class MyCourses extends React.Component {
                 className="my-courses"
             >
                 <MyCoursesCurrent />
-                <MyCoursesPast    />
+                <MyCoursesPast />
             </TourRegion>
         );
     }
 }
+
+export default MyCourses

tutor/src/models/user.ts

@@ -13,7 +13,7 @@ import urlFor from '../api'
 export interface UserEventPayload {
     category: string
     code: string
-    data: any
+    data?: any
 }