Introduction to JavaScript – Comments

Lesson Plan: Introduction to JavaScript Comments

Objective:

By the end of this lesson, students will be able to:

• Understand the purpose of comments in JavaScript.
• Write both single-line and multi-line comments in JavaScript.
• Explain how comments can enhance code readability and collaboration.

1. Introduction to Comments (5 mins)

• What are Comments?
  • Comments are lines in the code that are ignored by the JavaScript engine.
  • Their purpose is to explain the code or leave notes for future reference.
  • Comments do not affect the actual execution of the script.
• Why Use Comments?
  • Increase code readability.
  • Help collaborators understand the code.
  • Can be used to temporarily disable code during debugging.

  Example:

2. Single-Line Comments (5 mins)

• Syntax:
  • Use // to create a single-line comment.
• Usage:
  • Place comments on a new line or at the end of a code line.

  Examples:

Practice Exercise:

• Add a comment above the following line of code to explain what it does:

3. Multi-Line Comments (5 mins)

• Syntax:
  • Use /* */ to create a comment that spans multiple lines.
• Usage:
  • Useful for longer explanations or temporarily commenting out blocks of code.

  Example:

Practice Exercise:

• Use a multi-line comment to explain the following block of code:

4. Best Practices for Writing Comments (5 mins)

• Keep comments concise.
  Avoid long, unnecessary comments. Instead, focus on explaining complex logic or assumptions.
• Don’t over-comment.
  Comment where necessary, but let the code speak for itself when it’s self-explanatory.
• Stay consistent.
  Use a consistent format for comments throughout your project to maintain readability.Good Example:

Bad Example:

5. Final Exercise (10 mins)

• Write a short JavaScript function and add comments to explain each step.Example task:

• Challenge:
  • Write a function that calculates the average of an array of numbers.
  • Add both single-line and multi-line comments to explain each part.

6. Conclusion (5 mins)

• Summarize the purpose and types of comments.
• Emphasize that comments are important for readability and maintainability, especially when working in teams.

Homework:

• Review a simple JavaScript project and add comments to explain the code.

This lesson plan introduces JavaScript comments in a practical way, combining explanation with hands-on exercises.