Single-line comments are used to add a brief description of a single line of code. They begin with two forward slashes (//) and end at the end of the line. Here is an example:
let number = 10; // this is a variable assignment
Single-line comments are typically used for short descriptions of code and are useful for quickly identifying the purpose of a particular line.
Multi-line comments, also known as block comments, are used to describe a block of code or to add detailed comments about a single line of code. They begin with
/* and end with
*/. Here is an example:
/* This is a multi-line comment It can span across multiple lines */
Multi-line comments are useful for providing more detailed information about a block of code, such as explaining the purpose of a function or describing a complex algorithm.
When choosing between single-line and multi-line comments, consider the amount of information you need to convey. Single-line comments are best for short descriptions, while multi-line comments are better suited for longer explanations.
Use Comments Sparingly
Although comments are helpful, it’s important not to overuse them. Too many comments can clutter the code and make it difficult to read. Only add comments when necessary, such as when explaining complex logic or providing details about the code’s purpose.
Adopting a consistent commenting convention is crucial for maintaining readable code. Many developers use the “//” symbol to indicate a single-line comment, and the “/* */” symbols to indicate a multi-line comment. Others use a specific format for their comments, such as JSDoc. Whatever convention you choose, make sure to follow it consistently throughout your code.
Comment as You Code
It’s easy to put off adding comments until the end of a project, but this can lead to errors and confusion. Adding comments as you code ensures that your comments accurately reflect the code you’ve written. This also makes it easier to catch errors or potential problems early on in the development process.
1. Writing Commented-Out Code
It’s common for developers to leave commented-out code in their files. This can be problematic for several reasons. Firstly, commented-out code takes up space and can make files harder to navigate. Secondly, commented-out code can be confusing for other developers who may not know why the code was commented out in the first place.
To avoid this mistake, remove any commented-out code from your files. If you want to keep a record of old code, use version control software like Git.
2. Writing Inaccurate or Outdated Comments
Comments that don’t match the code they describe can be confusing and misleading. Additionally, comments that are outdated and no longer apply to the code can cause confusion. For example, if you change a variable name but don’t update the comment describing it, other developers may be confused.
To avoid this mistake, make sure your comments accurately reflect the code you’re describing. If you make changes to your code, update the corresponding comments.
3. Writing Unclear or Vague Comments
Comments that are too vague or unclear can be just as confusing as no comments at all. For example, a comment that simply says “set a variable” doesn’t provide any context or explanation.
To avoid this mistake, make your comments as descriptive as possible. Provide context and explain why certain code is necessary or what it does. This will help other developers understand your code more easily.
Why should I comment my code?
Commenting your code is essential because it helps other developers understand your code. It also makes it easier for you to revisit your code later and quickly understand what it does.
How can I make my comments more descriptive?
When writing comments, aim for clarity and detail. Describe what your code does in each section and be sure to include any important details that readers may need. Avoid vague or confusing comments that don’t add value.
One common mistake is writing comments that are too vague or don’t provide enough context. Another mistake is writing comments that are too long and make the code difficult to read. Always aim for a balance between informative and concise comments.
Do I need to comment every line of code?
No, not every line of code needs to be commented. However, you should aim to comment any sections of code that may be difficult for others to understand or that perform a crucial function within your code.
What are some commenting conventions that developers use?
Some common commenting conventions include using block comments for function and class declarations, using single line comments for code explanations, and using descriptive names for variables and functions.
Is it possible to comment out code?
Yes, you can comment out code by surrounding it with comment tags. This can be useful for temporarily disabling code or commenting out code that you may need to reference later.