Refactoring Legacy Code: The Matrix of Clean Code

Short summary

The article walks through using the Extract Method refactoring pattern to break down a monolithic processOrder function into small, named, testable units. It covers the benefits of improved readability, testability, reuse, and bug isolation, along with common pitfalls like over-extracting and leaking state. A practical JavaScript before-and-after example demonstrates transforming a 218-line function into a clean sequence of well-named helper calls.

• •Extract Method turns monolithic functions into readable sequences of named, testable steps
• •Common pitfalls include over-extracting, leaking state, and extracting too little with meaningless names
• •The approach is incremental — no full system rewrite required

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