Why Reading Code Matters
If writing code is building, then reading code is reverse engineering How to Read Other People’s Code. As developers, we often spend more time reading than writing code—yet it’s a skill many overlook. Whether you’re contributing to open source, debugging legacy code, or joining a new team, your ability to read and understand someone else’s code will set you apart.
“Programs must be written for people to read, and only incidentally for machines to execute.” — Harold Abelson
How to Read Other People’s Code
Table of Contents
How to Read Other People’s Code
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Why Reading Code Is Hard (and Normal!)
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Key Benefits of Learning to Read Code
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How to Approach Unfamiliar Codebases
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Tools That Help Decode Code
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Common Mistakes When Reading Code
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Best Practices for Understanding Code Logic
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Learning by Reading Open Source Projects
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Internalizing Patterns and Styles
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How to Take Notes While Reading Code
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Final Thoughts and Resources
- How to Read Other People’s Code
1. Why Reading Code Is Hard (and Normal!)
Reading someone else’s code can feel overwhelming, especially when it’s poorly documented, lacks consistency, or uses unfamiliar syntax How to Read Other People’s Code .
Reasons it can be tough:
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Different coding styles or naming conventions
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Lack of or outdated documentation
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Complex dependencies
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Implicit logic and uncommented code
- How to Read Other People’s Code
But here’s the good news: it gets easier with practice. Just like reading books in a new language, code becomes easier to parse over time.
2. Key Benefits of Learning to Read Code
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Debug faster: Spot bugs and logic errors in existing code.
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Collaborate effectively: Understand teammates’ code contributions.
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Accelerate learning: Discover new techniques, libraries, and patterns.
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Enhance code quality: Reading code informs your own writing style.
3. How to Approach Unfamiliar Codebases
Approaching a large project can feel like walking into a maze. Here’s a strategic breakdown:
Start with the README
Always begin with README.md, documentation, or wikis. They give an overview of purpose, setup, and structure.
Understand the File Structure
How to Read Other People’s Code
Identify:
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Entry points (e.g.,
index.js,main.py) -
Key modules/components
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Configuration files (
.env,package.json, etc.)
Find the Main Flow
Ask: What happens first when the app runs? Trace execution from the start.
Use Logs or Breakpoints
Walk through the app using breakpoints or console.log() to understand the flow.
4. Tools That Help Decode Code
These tools make reading easier:
| Tool | Purpose |
|---|---|
| VS Code | Navigate large codebases with minimaps, breadcrumbs |
| Sourcegraph | View and search source code repositories |
| Git Blame | See who wrote which lines (and why) |
| CodeLens (VS Code) | Show references, Git history, and tests inline |
| Debugger | Step through code execution |
5. Common Mistakes When Reading Code
Avoid these traps:
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Trying to understand everything at once
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Skipping docs or comments
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Ignoring function and variable names
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Reading bottom-up instead of top-down
Instead, focus on grasping the intent before the details.
6. Best Practices for Understanding Code Logic
Look for Patterns
Identify repeated logic or structure—this helps you predict what’s next.
Break Code into Chunks
Don’t read the entire file line by line. Understand one module, function, or class at a time.
Ask These Questions:
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What does this function do?
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What inputs/outputs does it handle?
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Where is it called?
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What side effects occur?
7. Learning by Reading Open Source Projects
Reading open-source code is one of the fastest ways to level up.
How to Start:
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Pick projects you use or are curious about.
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Start with smaller repos or beginner-friendly tags like good first issue.
Recommended GitHub Projects:
8. Internalizing Patterns and Styles
As you read more code, you’ll naturally begin to recognize:
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Common design patterns
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Idiomatic syntax in various languages
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Best practices and anti-patterns
Pro Tip: Maintain a “Code Journal” with snippets and explanations of things you found useful.
9. How to Take Notes While Reading Code
Use tools like:
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Notion or Obsidian for structured notes
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Code snippets with explanations
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Flowcharts to visualize logic
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Comments (non-committed) inside the code to annotate learning
10. Final Thoughts and Resources
Reading other people’s code is not just a technical skill—it’s a mindset. It’s about curiosity, patience, and persistence. The more you do it, the more intuitive it becomes.
