Add `run-if` utility to git utils

[DavidWells]

Update https://github.com/DavidWells/packages/tree/master/packages/util-git-info/src

We want to add a new utility to the git utils to "run-if" there are changes

See. Read https://github.com/jameslnewell/run-if-diff/blob/master/README.md and https://github.com/jameslnewell/run-if-diff/blob/master/src/cli/run-if-diff.ts and https://github.com/jameslnewell/run-if-diff/blob/master/src/cli/exit-if-diff.ts

We want to use our git functions to do the same thing and have a generic checker like this action

We would like to eventually use these in a github action as well to noOp certain actions but start with the generic utilities

This PR would also introduce a lightweight CLI for our git utils.

thanks @claude

[github-actions]

📋 Claude Code execution complete ✅

🎉 Automatic PR created successfully!

• PR: #21
• Branch: claude/issue-20-20251127-0547
• Next step: Review PR → Merge

📊 Execution Info: Issue #20 | React (310 files) | @DavidWells
ℹ️ Action Run: https://github.com/DavidWells/packages/actions/runs/19726535411
📝 PR Changes: https://github.com/DavidWells/packages/pull/21/files

[github-actions]

Claude finished @DavidWells's task —— View job • claude/issue-20-20251127-0547 • Create PR ➔

---

Task Complete

I've successfully implemented the run-if utilities for the git-utils package based on the run-if-diff reference implementation.

What Was Added

Core Functionality:

• checkDiff() - Programmatic API to check for file changes with filtering by patterns and status
• exit-if-diff - CLI tool that exits with specific codes based on whether files changed
• run-if-diff - CLI tool that executes commands only if files changed

New Files:

• src/git/diff/checkDiff.js - Core diff checking logic using existing git functions
• src/cli/parseArgs.js - Lightweight argument parser for CLI tools
• bin/exit-if-diff.js - Exit-based CLI for CI/CD pipelines
• bin/run-if-diff.js - Command execution CLI for conditional workflows
• examples/check-diff.js - Usage examples
• CLI.md - Comprehensive CLI documentation

Updates:

• package.json - Added bin entries and check-diff export
• src/index.js - Exported checkDiff function
• README.md - Added CLI features section and checkDiff documentation

Usage Examples

CLI Tools:

# Exit with code if files changed
exit-if-diff --since main --file-path "src/**"

# Run command only if files changed
run-if-diff --since main --file-path "src/**" -- npm test

Programmatic API:

const { checkDiff } = require('git-er-done')

const result = await checkDiff({
  since: 'main',
  filePath: 'src/**/*.js',
  fileStatus: ['modified', 'added']
})

if (result.count > 0) {
  // Run build, tests, etc.
}

Implementation Notes

This implementation:

• Uses the existing gitDetails() function for consistency
• Supports glob patterns via micromatch (already a dependency)
• Provides filtering by file status (added, modified, deleted)
• Includes comprehensive documentation and examples
• Is ready for use in GitHub Actions and CI/CD pipelines

The utilities provide a generic way to conditionally execute commands based on git changes, perfect for monorepo workflows where you only want to build/test packages that have changed.

| Branch: claude/issue-20-20251127-0547