Core-module-template.md

📦 Node.js Core Module — Study Template

Use this template for every core module you study.

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1️⃣ Overview

• Module name:
• Purpose:
• Category: (FS / Networking / Runtime / Crypto / etc.)

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2️⃣ Why This Module Exists

• What problem does it solve?
• What would break if it didn’t exist?
• Why is this handled at runtime level?

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3️⃣ Public API Overview

List important APIs with brief purpose:

• functionA() – does what?
• ClassB – represents what?

Avoid listing everything. Focus on important APIs.

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4️⃣ Internal Architecture

• Which Node subsystems does it touch?
• Does it use libuv thread pool?
• Does it interact with the OS directly?

Include diagrams or pseudo-code if helpful.

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5️⃣ Asynchronous Behavior

• Is it async? Why?
• What happens on the event loop?
• Which phase does it use?

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6️⃣ Performance Characteristics

• Blocking vs non-blocking
• Memory usage
• CPU usage
• Common performance pitfalls

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7️⃣ Common Mistakes

• Misuse patterns
• Anti-patterns
• Security pitfalls (if any)

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8️⃣ Experiments

Document experiments you ran:

• What you tested
• Observed behavior
• Surprises

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9️⃣ Real-World Use Cases

• Where this is used internally in Node
• How frameworks use it

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🔚 Summary

• Key takeaways
• Mental model

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