Coding / 5 min read
A Simple Guide to Debugging Your Code
Debugging is less about being clever and more about being methodical. A calm process beats frantic changes every time, especially when the bug is hiding in plain sight.
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Reproduce reliably
If you cannot reproduce the bug consistently, you cannot verify a fix. Narrow down the exact steps, inputs, and environment that trigger it. Save those steps in notes so you can test against them after every change.
Sometimes the issue only appears under specific data or timing. Simplify inputs until the bug still appears, or until it disappears. The smallest reproducible case is your best friend.
Read the error with care
Error messages often point directly to the problem. Read the full message, stack trace, and line numbers. Look for the first frame in your own code, not just library code, as that's usually where your assumptions break.
If the message is vague, search for it with context. But avoid copying random fixes without understanding why they apply. Understanding beats cargo-culting.
Form a hypothesis and test
Based on evidence, guess what might be wrong. Change one thing at a time and test against your reproducible case. This disciplined approach prevents new bugs while you hunt the old one.
- Observe: What actually happens vs what should happen?
- Hypothesize: What's the most likely cause?
- Isolate: Change one variable and test.
- Verify: Confirm the fix or rule out the hypothesis.
Use the right tools
Logs, debuggers, and print statements all have their place. Use a debugger to step through tricky logic. Add temporary logs with clear labels. Remove debug code once you've fixed the issue to keep things clean.
For web issues, check the console, network tab, and local state. For data issues, inspect the actual values flowing through your functions rather than assuming them.
Take a break when stuck
If you've been chasing a bug for over an hour with no progress, step away. A short walk or rest often reveals the missing piece. Fresh eyes catch the typo, wrong assumption, or off-by-one that persistence blinded you to.
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