Development: Fix console errors on course overview page

[cremertim]

Checklist

General

• This is a small issue that I tested locally and was confirmed by another developer on a test server.
• I chose a title conforming to the naming conventions for pull requests.

Motivation and Context

If you are in the CourseOverview Page, every single components throws console errors at startup time due to missing undefined checks.

Description

I added the undefine check for every CourseOverviewComponent

Steps for Testing

Prerequisites:

• 1 Student

1. Log in to Artemis
2. Navigate to Course Overview
3. Open the console
4. Click through every tab

Testserver States

Note

These badges show the state of the test servers.
Green = Currently available, Red = Currently locked
Click on the badges to get to the test servers.

Review Progress

Performance Review

• I (as a reviewer) confirm that the client changes (in particular related to REST calls and UI responsiveness) are implemented with a very good performance even for very large courses with more than 2000 students.
• I (as a reviewer) confirm that the server changes (in particular related to database calls) are implemented with a very good performance even for very large courses with more than 2000 students.

Code Review

• Code Review 1
• Code Review 2

Manual Tests

• Test 1
• Test 2

Exam Mode Test

• Test 1
• Test 2

Performance Tests

• Test 1
• Test 2

Screenshots

Summary by CodeRabbit

• Bug Fixes
  • Implemented null-safe checks for faqs and filteredFaqs in the course FAQ component to prevent runtime errors.
  • Enhanced dropdown menu functionality in the course overview component with null-safe operators to avoid errors when closing the menu.
  • Improved sidebar component robustness by adding null-safe navigation for sidebarData properties, preventing potential issues when accessing undefined values.

[coderabbitai]

Walkthrough

The changes involve the implementation of null-safe checks across multiple HTML template files in an Angular application. Specifically, the course-faq.component.html, course-overview.component.html, and sidebar.component.html files have been updated to use the optional chaining operator (?.) to prevent runtime errors when accessing potentially null or undefined objects. These modifications ensure that the application handles cases where data may not be present without crashing.

Changes

File Path	Change Summary
src/main/webapp/app/overview/course-faq/course-faq.component.html	Updated length checks for faqs and filteredFaqs arrays to use optional chaining (?.).
src/main/webapp/app/overview/course-overview.component.html	Added null-safe operator (?.) to click event handlers for closing dropdown menus to prevent errors.
src/main/webapp/app/shared/sidebar/sidebar.component.html	Introduced null-safe navigation for sidebarData properties to prevent errors when accessing potentially undefined values.

Possibly related PRs

• Communication: Add default message to empty FAQ view #9467: This PR is directly related as it modifies the course-faq.component.html file, introducing conditional rendering for messages based on the state of the faqs array, which aligns with the null-safe checks introduced in the main PR.

Suggested labels

bugfix, ready for review, small

Suggested reviewers

• JohannesStoehr
• SimonEntholzer
• krusche

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[coderabbitai]

Actionable comments posted: 0

🧹 Outside diff range and nitpick comments (3)

src/main/webapp/app/overview/course-faq/course-faq.component.html (1)

38-38: Approved with suggestion: Consider adding null check for faqs.length.

The change correctly implements a null-safe check using the optional chaining operator (?.) for the filteredFaqs array, which prevents potential runtime errors. The use of the @if directive adheres to the provided coding guidelines.

However, there's a potential issue with faqs.length > 0 not using the optional chaining operator. To ensure complete null safety, consider updating this part of the condition as well.

Consider applying this change:

-@if (filteredFaqs?.length === 0 && faqs.length > 0) {
+@if (filteredFaqs?.length === 0 && faqs?.length > 0) {

This will prevent potential runtime errors if faqs is null or undefined.

src/main/webapp/app/shared/sidebar/sidebar.component.html (1)

Line range hint 51-51: LGTM: Null-safe checks implemented correctly. Consider improving readability.

The changes in this line are well-implemented:

1. Multiple null-safe checks for sidebarData using the optional chaining operator (?.) enhance the robustness of the code.
2. The use of @if instead of *ngIf aligns with the provided coding guidelines for Angular syntax.

These modifications will help prevent runtime errors and keep the code up-to-date with modern Angular practices.

However, the line contains complex conditional logic. Consider breaking it down into smaller, more readable parts for improved maintainability.

Here's a suggestion to improve readability:

@if (shouldDisplayNoDataMessage()) {
  <div
    [ngClass]="{ 'content-height-dev': !isProduction || isTestServer }"
    [jhiTranslate]="getNoDataMessageKey()"
    class="mt-2 text-center scrollable-item-content"
  ></div>
}

// In the component class:
shouldDisplayNoDataMessage(): boolean {
  return !this.sidebarData?.ungroupedData || 
         !(this.sidebarData?.ungroupedData | searchFilter: ['title', 'type'] : this.searchValue)?.length;
}

getNoDataMessageKey(): string {
  return (this.sidebarDataBeforeFiltering?.ungroupedData?.length ?? 0) > 0 && this.sidebarData.ungroupedData?.length === 0
    ? 'artemisApp.courseOverview.general.noElementFoundWithAppliedFilter'
    : 'artemisApp.courseOverview.general.noDataFound';
}

This approach moves the complex logic to the component class, making the template more readable and easier to maintain.

src/main/webapp/app/overview/course-overview.component.html (1)

Line range hint 1-282: Good adherence to coding guidelines, consider component decomposition for improved maintainability.

The template consistently uses the new Angular syntax with @if and @for directives, adhering to the provided coding guidelines. This is a positive aspect of the implementation.

However, the template's complexity and length suggest that it might benefit from being broken down into smaller, more manageable components. This could improve maintainability and readability of the code.

Consider decomposing this large template into smaller, reusable components. This could make the code easier to maintain and understand in the long run. For example, you could create separate components for the sidebar, course title bar, and main content area.

📜 Review details

Configuration used: .coderabbit.yaml
Review profile: CHILL

📥 Commits

Files that changed from the base of the PR and between 53692bc and 3ec9890.

📒 Files selected for processing (3)

• src/main/webapp/app/overview/course-faq/course-faq.component.html (1 hunks)
• src/main/webapp/app/overview/course-overview.component.html (2 hunks)
• src/main/webapp/app/shared/sidebar/sidebar.component.html (1 hunks)

🧰 Additional context used

📓 Path-based instructions (3)

src/main/webapp/app/overview/course-faq/course-faq.component.html (1)

Pattern src/main/webapp/**/*.html: @if and @for are new and valid Angular syntax replacing *ngIf and *ngFor. They should always be used over the old style.

src/main/webapp/app/overview/course-overview.component.html (1)

Pattern src/main/webapp/**/*.html: @if and @for are new and valid Angular syntax replacing *ngIf and *ngFor. They should always be used over the old style.

src/main/webapp/app/shared/sidebar/sidebar.component.html (1)

Pattern src/main/webapp/**/*.html: @if and @for are new and valid Angular syntax replacing *ngIf and *ngFor. They should always be used over the old style.

🔇 Additional comments (6)

src/main/webapp/app/overview/course-faq/course-faq.component.html (1)

30-30: LGTM! Null safety improved and modern Angular syntax used.

The change correctly implements a null-safe check using the optional chaining operator (?.) for the faqs array. This prevents potential runtime errors if faqs is null or undefined. Additionally, the use of the @if directive adheres to the provided coding guidelines, which recommend using @if over *ngIf.

src/main/webapp/app/shared/sidebar/sidebar.component.html (3)

28-28: LGTM: Null-safe check and new Angular syntax implemented correctly.

The changes in this line are well-implemented:

1. The null-safe check for sidebarData using the optional chaining operator (?.) enhances the robustness of the code.
2. The use of @if instead of *ngIf aligns with the provided coding guidelines for Angular syntax.

These modifications will help prevent runtime errors and keep the code up-to-date with modern Angular practices.

---

Line range hint 71-71: LGTM: Null-safe check and new Angular syntax implemented correctly.

The changes in this line are well-implemented:

1. The null-safe check for sidebarData using the optional chaining operator (?.) enhances the robustness of the code.
2. The use of @if instead of *ngIf aligns with the provided coding guidelines for Angular syntax.

These modifications will help prevent runtime errors and keep the code up-to-date with modern Angular practices.

---

Line range hint 28-71: Overall assessment: Improvements in code robustness and adherence to modern Angular practices.

The changes made to this file consistently implement the following improvements:

1. Addition of null-safe checks using the optional chaining operator (?.) for sidebarData and its properties.
2. Adoption of the new Angular syntax @if instead of *ngIf.

These modifications collectively enhance the code in the following ways:

• Increased robustness by preventing potential runtime errors due to undefined or null values.
• Improved alignment with modern Angular practices and syntax.
• Better handling of edge cases where data might be missing or undefined.

The changes effectively address the PR objective of removing console errors on the CourseOverviewPage by implementing undefined checks. This will lead to a more stable user experience.

One area for potential further improvement is the readability of complex conditional logic, as noted in a previous comment.

Overall, these changes represent a positive step towards more reliable and maintainable code.

src/main/webapp/app/overview/course-overview.component.html (2)

258-258: LGTM: Null-safe operator added to prevent potential errors.

The addition of the null-safe operator ?. to itemsDrop?.close() is a good practice. It prevents potential runtime errors if itemsDrop is undefined, aligning with the PR's objective of removing console errors on the Course Overview Page.

---

277-277: LGTM: Consistent use of null-safe operator.

The addition of the null-safe operator ?. to itemsDrop?.close() in this template is consistent with the previous change. It maintains a uniform approach to preventing potential runtime errors throughout the component.

[krusche]

Code looks good 👍