feat: support jumping to specific xblock id (openedx#1427)

Adds ability to pass `jumpToId` query param to iframe url as id hash to
be used by browser to scroll to the correct xblock

src/courseware/course/sequence/Unit/index.jsx

@@ -1,5 +1,6 @@
 import PropTypes from 'prop-types';
 import React from 'react';
+import { useSearchParams } from 'react-router-dom';
 
 import { AppContext } from '@edx/frontend-platform/react';
 import { useIntl } from '@edx/frontend-platform/i18n';
@@ -23,6 +24,7 @@ const Unit = ({
   id,
 }) => {
   const { formatMessage } = useIntl();
+  const [searchParams] = useSearchParams();
   const { authenticatedUser } = React.useContext(AppContext);
   const examAccess = useExamAccess({ id });
   const shouldDisplayHonorCode = useShouldDisplayHonorCode({ courseId, id });
@@ -35,6 +37,7 @@ const Unit = ({
     view,
     format,
     examAccess,
+    jumpToId: searchParams.get('jumpToId'),
   }));
 
   const iframeUrl = getUrl();

src/courseware/course/sequence/Unit/index.test.jsx

@@ -1,6 +1,7 @@
 import React from 'react';
 import { when } from 'jest-when';
 import { formatMessage, shallow } from '@edx/react-unit-test-utils/dist';
+import { useSearchParams } from 'react-router-dom';
 
 import { useModel } from '@src/generic/model-store';
 
@@ -14,6 +15,7 @@ import { modelKeys, views } from './constants';
 import * as hooks from './hooks';
 
 jest.mock('./hooks', () => ({ useUnitData: jest.fn() }));
+jest.mock('react-router-dom');
 
 jest.mock('@edx/frontend-platform/i18n', () => {
   const utils = jest.requireActual('@edx/react-unit-test-utils/dist');
@@ -82,7 +84,11 @@ when(useModel)
 
 let el;
 describe('Unit component', () => {
+  const searchParams = { get: (prop) => prop };
+  const setSearchParams = jest.fn();
+
   beforeEach(() => {
+    useSearchParams.mockImplementation(() => [searchParams, setSearchParams]);
     jest.clearAllMocks();
     el = shallow(<Unit {...props} />);
   });

src/courseware/course/sequence/Unit/urls.js

@@ -1,5 +1,5 @@
 import { getConfig } from '@edx/frontend-platform';
-import { stringify } from 'query-string';
+import { stringifyUrl } from 'query-string';
 
 export const iframeParams = {
   show_title: 0,
@@ -12,15 +12,20 @@ export const getIFrameUrl = ({
   view,
   format,
   examAccess,
+  jumpToId,
 }) => {
   const xblockUrl = `${getConfig().LMS_BASE_URL}/xblock/${id}`;
-  const params = stringify({
-    ...iframeParams,
-    view,
-    ...(format && { format }),
-    ...(!examAccess.blockAccess && { exam_access: examAccess.accessToken }),
+  return stringifyUrl({
+    url: xblockUrl,
+    query: {
+      ...iframeParams,
+      view,
+      ...(format && { format }),
+      ...(!examAccess.blockAccess && { exam_access: examAccess.accessToken }),
+      jumpToId, // Pass jumpToId as query param as fragmentIdentifier is not passed to server.
+    },
+    fragmentIdentifier: jumpToId, // this is used by browser to scroll to correct block.
   });
-  return `${xblockUrl}?${params}`;
 };
 
 export default {

src/courseware/course/sequence/Unit/urls.test.js

@@ -1,12 +1,12 @@
 import { getConfig } from '@edx/frontend-platform';
-import { stringify } from 'query-string';
+import { stringifyUrl } from 'query-string';
 import { getIFrameUrl, iframeParams } from './urls';
 
 jest.mock('@edx/frontend-platform', () => ({
   getConfig: jest.fn(),
 }));
 jest.mock('query-string', () => ({
-  stringify: jest.fn((...args) => ({ stringify: args })),
+  stringifyUrl: jest.fn((arg) => ({ stringifyUrl: arg })),
 }));
 
 const config = { LMS_BASE_URL: 'test-lms-url' };
@@ -21,41 +21,43 @@ const props = {
 
 describe('urls module getIFrameUrl', () => {
   test('format provided, exam access and token available', () => {
-    const params = stringify({
-      ...iframeParams,
-      view: props.view,
-      format: props.format,
-      exam_access: props.examAccess.accessToken,
+    const url = stringifyUrl({
+      url: `${config.LMS_BASE_URL}/xblock/${props.id}`,
+      query: {
+        ...iframeParams,
+        view: props.view,
+        format: props.format,
+        exam_access: props.examAccess.accessToken,
+      },
     });
-    expect(getIFrameUrl(props)).toEqual(`${config.LMS_BASE_URL}/xblock/${props.id}?${params}`);
+    expect(getIFrameUrl(props)).toEqual(url);
   });
   test('no format provided, exam access blocked', () => {
-    const params = stringify({ ...iframeParams, view: props.view });
+    const url = stringifyUrl({
+      url: `${config.LMS_BASE_URL}/xblock/${props.id}`,
+      query: { ...iframeParams, view: props.view },
+    });
     expect(getIFrameUrl({
       id: props.id,
       view: props.view,
       examAccess: { blockAccess: true },
-    })).toEqual(`${config.LMS_BASE_URL}/xblock/${props.id}?${params}`);
+    })).toEqual(url);
   });
-  test('src and dest languages provided', () => {
-    const params = stringify({
-      ...iframeParams,
-      view: props.view,
-      src_lang: 'test-src-lang',
-      dest_lang: 'test-dest-lang',
+  test('jumpToId and fragmentIdentifier is added to url', () => {
+    const url = stringifyUrl({
+      url: `${config.LMS_BASE_URL}/xblock/${props.id}`,
+      query: {
+        ...iframeParams,
+        view: props.view,
+        format: props.format,
+        exam_access: props.examAccess.accessToken,
+        jumpToId: 'some-xblock-id',
+      },
+      fragmentIdentifier: 'some-xblock-id',
     });
     expect(getIFrameUrl({
       ...props,
-      srcLanguage: 'test-src-lang',
-      destLanguage: 'test-dest-lang',
-    })).toEqual(`${config.LMS_BASE_URL}/xblock/${props.id}?${params}`);
-  });
-  test('src and dest languages provided are the same', () => {
-    const params = stringify({ ...iframeParams, view: props.view });
-    expect(getIFrameUrl({
-      ...props,
-      srcLanguage: 'test-lang',
-      destLanguage: 'test-lang',
-    })).toEqual(`${config.LMS_BASE_URL}/xblock/${props.id}?${params}`);
+      jumpToId: 'some-xblock-id',
+    })).toEqual(url);
   });
 });