Changes in Client Requirement
Explore how to adapt a JavaScript budget tracker from a command-line interface to a web-based user interface. Understand the importance of separating core logic from presentation, handle evolving client requirements, and use AI assistance to convert CLI functions into web components. Gain practical skills in maintaining clean code foundations while enhancing user experience for broader audiences.
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You built a resilient command-line budget tracker that does more than follow the ideal path. It parses inputs safely with try...catch, rejects invalid entries, normalizes categories, prevents accidental deletions, and generates a clear report that includes income, total expenses, remaining balance, and per-category totals. Behind the scenes, you kept the data model small, with income as a number, expenses as an array of objects, and the logic organized, efficient, and easy to test.
In short, you built a solid, reliable core.
The curveball
A week later, your client contacts you after a demo with the operations team:
“The command line works well for your team, but our front desk and new hires aren’t comfortable with terminals. Can we get a simple web app with buttons, fields, and a report section—something user-friendly?”
One of the most common realities in software is that requirements change. New stakeholders appear, workflows become clearer, and prototypes often grow into full products. This isn’t failure; it’s progress. The app can adapt easily because the logic is separate from the interface.
In practice, ...