feat: hide sidebar on screen resize (#1720)

Adds an event handler on the window resize to check if the sidebar isOpen and the size of the viewport is smaller than the sidebar display to hide the sidebar and prevent it from blocking the course view.

src/courseware/course/sidebar/sidebars/course-outline/CourseOutlineTray.test.jsx

@@ -102,6 +102,21 @@ describe('<CourseOutlineTray />', () => {
     expect(mockToggleSidebar).toHaveBeenCalledWith(null);
   });
 
+  it('collapses sidebar correctly when screen is resized', async () => {
+    const mockToggleSidebar = jest.fn();
+    await initTestStore();
+    renderWithProvider({ toggleSidebar: mockToggleSidebar });
+
+    const collapseBtn = screen.getByRole('button', { name: messages.toggleCourseOutlineTrigger.defaultMessage });
+    expect(collapseBtn).toBeInTheDocument();
+
+    // Simulate screen resize
+    window.innerWidth = 500;
+    window.dispatchEvent(new Event('resize'));
+
+    expect(mockToggleSidebar).toHaveBeenCalledWith(null);
+  });
+
   it('navigates to section or sequence level correctly on click by back/section button', async () => {
     const user = userEvent.setup();
     await initTestStore();

src/courseware/course/sidebar/sidebars/course-outline/hooks.js

@@ -1,7 +1,10 @@
-import { useContext, useEffect, useState } from 'react';
+import {
+  useContext, useEffect, useLayoutEffect, useState,
+} from 'react';
 import { useDispatch, useSelector } from 'react-redux';
 import { useParams } from 'react-router-dom';
 import { sendTrackEvent, sendTrackingLogEvent } from '@edx/frontend-platform/analytics';
+import { breakpoints } from '@openedx/paragon';
 
 import { useModel } from '@src/generic/model-store';
 import { LOADED } from '@src/constants';
@@ -54,10 +57,14 @@ export const useCourseOutlineSidebar = () => {
   } = course.entranceExamData || {};
   const isActiveEntranceExam = entranceExamEnabled && !entranceExamPassed;
 
+  const collapseSidebar = () => {
+    toggleSidebar(null);
+    window.sessionStorage.setItem('hideCourseOutlineSidebar', 'true');
+  };
+
   const handleToggleCollapse = () => {
     if (currentSidebar === ID) {
-      toggleSidebar(null);
-      window.sessionStorage.setItem('hideCourseOutlineSidebar', 'true');
+      collapseSidebar();
     } else {
       toggleSidebar(ID);
       window.sessionStorage.removeItem('hideCourseOutlineSidebar');
@@ -107,6 +114,21 @@ export const useCourseOutlineSidebar = () => {
     }
   }, [courseId, isEnabledSidebar, courseOutlineShouldUpdate]);
 
+  // Collapse sidebar if screen resized to a width that displays the sidebar automatically
+  useLayoutEffect(() => {
+    const handleResize = () => {
+      // breakpoints.large.maxWidth is 1200px and currently the breakpoint for showing the sidebar
+      if (currentSidebar === ID && global.innerWidth < breakpoints.large.maxWidth) {
+        collapseSidebar();
+      }
+    };
+
+    global.addEventListener('resize', handleResize);
+    return () => {
+      global.removeEventListener('resize', handleResize);
+    };
+  }, [isOpen]);
+
   return {
     courseId,
     unitId,