git-diff-byte-count

A Python script that compares code size between git commits with comments and whitespace stripped out, giving you a true measure of whether a refactor is actually reducing code size.

Overview

When refactoring, it's easy to fool yourself with raw line counts — moving code into helpers or splitting files can make diffs look large while actual logic stays the same (or grows). This script cuts through that noise by stripping comments and whitespace before measuring, so you see only the meaningful code bytes that changed.

It compares every changed file between a base commit and HEAD, showing per-file before/after byte counts and a total summary.

Prerequisites

• Python 3
• A git repository with at least one commit

Usage

git diff-byte-count [<commit>]

Parameters

• <commit>: Commit to compare HEAD against (default: HEAD~1)

Options

• -h, --help: Show help message and exit

Examples

# Compare against the previous commit (default)
git diff-byte-count

# Compare against a named branch
git diff-byte-count main

# Compare the last 10 commits
git diff-byte-count HEAD~10

# Compare against a specific commit
git diff-byte-count a1b2c3d4

Supported File Types

Extension	Comment styles stripped
.ts, .tsx, .js, .jsx	// line comments, /* */ block comments
.py	# line comments (shebangs preserved)
.sh	# line comments (shebangs preserved)

Output Format

Each changed file is shown on one line with before/after byte counts and the difference. Green indicates code reduction, red indicates growth.

src/utils.ts                    1024 ->      896 (-128 bytes)
src/main.ts                      512 ->      640 (+128 bytes)

-----------------------------------------------------------------------
Total:                          1536 ->     1536 (+0 bytes, 0.0% change)

Use Cases

• Refactoring validation: Confirm a refactor genuinely reduces code, not just moves it
• Code review: Quantify the actual complexity change in a PR
• Tracking progress: Measure code reduction goals over a range of commits