Devlog 1 — Building a CLI Calculator

What I set out to build :

A command-based CLI calculator using Node.js that can take input directly from the terminal and perform operations like addition, subtraction multiplication and division.

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What I learned:

• How process.argv works for handling command-line input

• Why "5" + "3" results in "53" (strings vs numbers in JavaScript)

• How to convert inputs properly using Number()

• The difference between calling a function and referencing it

• How to implement a command map using commands[cmd]()

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Biggest struggle:

Understanding how to structure the command system cleanly without relying on long and messy if/else chains.

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Breakthrough moment:

Realizing that I could store functions inside an object and dynamically execute them based on user input. That made the whole system feel much cleaner and scalable.

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Current features:

• Supports add, sub, mul and div commands
• Handles invalid commands with basic error messaging
• Uses a command map for cleaner execution logic

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Next steps:

• Add scientific functions like sqrt, pow, and log
• Improve input validation
• Potentially add a history system

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Reflection:

Started this knowing almost nothing about CLI tools or Node.js input handling and ended up building a working command-based system. It’s simple but it actually feels like the foundation of something bigger.