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  • 🦥 How To Write Good Code Comments

🦥 How To Write Good Code Comments

Dec 11, 2024

Hello friends!

Welcome to another late issue of Sloth Bytes (whoops😅)

🦥 No selling out today

I am genuinely considering selling feet pics, so if you work at a company with a marketing budget please forward this to your boss immediately or the feet come out.

Save yourself and learn more about sponsoring

Giphy

A female sloth will have 1 baby approximately every 2 years.

Code Comments

Ever stared at your code from 6 months ago thinking “why did I write this garbage?”

You probably left some comments that weren’t necessary or didn’t leave a comment at all…

Let's fix that problem by talking about how to write comments that actually help future you (and your team).

The Golden Rule of Comments

❌ Explaining what the code does

✅ Explaining why the code does it

Comments That Hurt More Than Help

// Increment counter by 1 (pretty obvious...)
counter += 1;

// Loop through array (also pretty obvious...)
for (const item of items) {

These comments… well

They serve absolutely NO PURPOSE.

The code already tells us what it does!

Comments that actually help

// Rate limit: Maximum 100 requests per minute per user
const THROTTLE_LIMIT = 100;

// Skip validation in test environment to improve test speed
if (!isTestEnv) validateUser(user);

// Reverse the array first to handle nested dependencies
// Example: C depends on B, B depends on A
tasks.reverse().forEach(processTask);

When to Comment (And When Not To)

Comment when:

  • Explaining business logic that isn't obvious

  • Documenting workarounds or gotchas

  • Warning about edge cases

  • Explaining "magic numbers"

  • Clarifying regular expressions

Don't comment when:

  • The code is self-explanatory

  • You can make the code clearer instead

  • You're commenting out code that you won’t use for a while (use version control)

Better Than Comments: Self-Documenting Code

❌ Poor names + comments:

// Check if user can access feature
// u = user and f = feature
function check(u, f) {
  return u.p.includes(f);
}

✅ Clear names (no comment needed):

function hasPermissionForFeature(user, featureName) {
  return user.permissions.includes(featureName);
}

Comment Checklist

  • Would this be comment unnecessary if the code was clearer?

  • Will this comment still be true in the future?

  • Does it explain the "why" not the "what"?

  • Is it up to date with the code?

  • Would you want to read this comment?

Remember

  • Comments are a last resort - clear code is better

  • Keep comments close to the code they describe

  • Update comments when you update code

  • Delete comments that no longer add value

  • Write comments like you're explaining to your future self

Pro Tip: Use keyboard shortcuts in your IDE to toggle comment blocks quickly.

In VS Code:

  • Windows/Linux: Ctrl + /

  • Mac: Cmd + /

Now go and fix your comments. Your future self will thank you.

If you want to keep learning

  • How to ask better programming questions — practice explaining context, intent, and what you already tried instead of dropping “help pls” into a Discord channel.

  • Get better at programming without writing more code — improve by reading other people’s code and studying the decisions behind it.

  • Version control explained — the correct place for old code instead of a 40-line commented-out graveyard.

  • Debugging techniques — learn how to leave useful context while you trace what actually went wrong.

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Devin is now available to take your jobs for $500/month

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Sora is out! You can use it at sora.com⁠ if you’re a ChatGPT Plus and Pro users.

ChatGPT Pro (4 minute read)

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Meet Willow, Google’s state-of-the-art quantum chip (9 minute read)

This new quantum chip demonstrates error correction and performance that paves the way to a useful, large-scale quantum computer.

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Thank you to everyone who submitted 😃 

There was a lot of submissions this time.

joshuahighley, RelyingEarth87, cheodoor, Saydfalls, pyGuy152, JamesHarryT, sonvalle, trgr-boi, ravener, tobiaoy, and many more (sorry got lazy!)

Is the Phone Number Formatted Correctly?

Create a function that accepts a string and returns true if it's in the format of a proper phone number and false if it's not. Assume any number between 0-9 (in the appropriate spots) will produce a valid phone number.

This is what a valid phone number looks like:

(123) 456-7890

Examples

isValidPhoneNumber("(123) 456-7890")
output = True

isValidPhoneNumber("1111)555 2345")
output = False

isValidPhoneNumber("098) 123 4567")
output = False

Notes

Don't forget the space after the closing parenthesis.

How To Submit Answers

Reply with

  • A link to your solution (github, twitter, personal blog, portfolio, replit, etc)

  • or if you’re on the web version leave a comment!

That’s all from me!

Have a great week, be safe, make good choices, and have fun coding.

If I made a mistake or you have any questions, feel free to comment below or reply to the email!

See you all next week.

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