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Refactoring

Refactoring Without Changing Behavior

Small improvements, every day. Leave the code better than you found it.

Codeo

By Codeo

May 6, 2025 · 8 min read · Intermediate

Refactoring is the discipline of changing the shape of code without changing what it does. The behaviour stays frozen; only the structure moves.

1. Green Before You Start

Refactoring without tests is just editing and hoping. Get to green first, then move in small, reversible steps.

npm test -- --watch
# stay green, one small step at a time
language: bash

2. Small Steps, Every Day

  1. Rename until the code says what it means.
  2. Extract the block that needed a comment.
  3. Inline the indirection nobody uses.
  4. Run the tests. Commit. Repeat.
Small steps. Big impact.

3. Leave It Better

The campsite rule scales: every file you touch gets a little cleaner than you found it. Do that for a year and the codebase becomes a place people want to work in.

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