Keeping Routines Focused

Functions doing too many things often contain 'and' in their description, exceed 200 lines, or have more than seven parameters. Apply the 'and' test: if you describe your function using 'and', it likely violates single responsibility. Break it into focused units, each handling one task.

Extract multi-responsibility routines into single-responsibility units by identifying distinct tasks within the function. For example, split a 300-line `processOrder` function into `validateOrder`, `calculatePricing`, and `saveOrder`. Maintain consistent abstraction level across extracted functions.

Single-responsibility functions enforce functional cohesion, making code easier to test, modify, and reuse. Smaller, focused routines are simpler to understand, less error-prone, and reduce maintenance burden by clearly defining what each function does.

Yes. Single responsibility applies during designing new functions, refactoring existing code, and code reviews. Check if routine descriptions contain 'and', exceed length thresholds, or have excessive parameters—these are signals to extract responsibilities into separate functions.

Functional cohesion means each routine performs one task exceptionally well. Enforcing cohesion with clear naming, consistent abstraction, and single responsibility reduces code complexity, improves testability, and makes codebases easier to navigate and maintain.

Use clear, descriptive names that reflect the single purpose of each function. Avoid generic names; instead use action-verb patterns like `validateOrder`, `calculatePricing`, or `saveOrder`. Clear naming supports functional cohesion and makes responsibilities immediately obvious.