test-driven-development

Test-driven development is a process where you write a failing test before any production code. The Red-Green-Refactor cycle involves writing a failing test, implementing minimal code to pass it, then refactoring for clean, maintainable code.

Write a failing test for the desired behavior, implement minimal code to make it pass, then refactor. This incremental cycle prevents regressions and drives modular design across JavaScript and TypeScript codebases for features and bug fixes.

Yes, test-driven development applies to refactoring across modern JavaScript and TypeScript codebases. You write tests to capture existing behavior before modifying code, ensuring incremental improvements maintain clean, testable results without regressions.

No, test-driven development enforces that a failing test must exist before any production code is written. You create the initial failing test yourself to define requirements, then implement code to achieve green passes.

Writing code without tests leads to fragile releases because requirements are not captured and validated before implementation. Test-driven development solves this by enforcing failing tests first, preventing regressions and encouraging modular, maintainable code.