feat: critical bug fixes and UX improvements

[jameswiltshire]

Summary

This PR addresses several critical issues and adds quality-of-life improvements to merge-jsonc.

Changes

Bug Fixes

1. Header Detection in Content Change Detection (fix: correct header detection)

• Problem: When outputting to JSONC/JSON5 files with headers enabled, the tool compared content without headers but wrote content with headers. This caused incorrect "no change" detection when only the header timestamp differed.
• Impact: Files wouldn't update even when the header timestamp changed, and dry-run previews didn't show headers that would actually be written.
• Solution: Changed and dry-run preview to use (with header) instead of (without header).
• Test Updates: Updated one test to explicitly disable headers when testing pure content change detection.

2. Missing Output Directory Creation (feat: create parent directories)

• Problem: Tool would fail with an error if the output path's parent directory didn't exist.
• Impact: Users had to manually create directories before running the tool.
• Solution: Added automatic parent directory creation in using with recursive option.
• Test Coverage: Added test case verifying nested directory creation works correctly.

Features

3. Improved Status Messages (feat: improve status messages and add --quiet flag)

• Enhanced Messages:

  • no_inputs: Now explains missing files and suggests --skip-missing
  • up_to_date: Shows count of input files and clarifies timestamp-based skip
  • no_content_change: Clearer explanation that merged content matches existing output
  • wrote: Includes count of merged files
  • wrote_with_backup: Shows file count alongside backup path

• New --quiet Flag (-q alias):

  • Suppresses all non-error output for scripting use cases
  • Errors still displayed for debugging
  • Useful in CI/CD pipelines and automated workflows

• Test Coverage: Updated all existing message tests and added 3 new tests for --quiet behavior.

Testing

All tests pass (85 tests):

• Core functionality: 16 tests
• CLI integration: 11 tests
• CLI module: 11 tests (3 new for --quiet)
• FS safety: 17 tests
• Features: 4 tests
• Config: 6 tests
• Timing/backup: 20 tests

Code coverage maintained at ~88%.

Breaking Changes

None. All changes are backwards compatible:

• Header behavior unchanged (default still enabled)
• Existing CLI flags work as before
• Message format changes are cosmetic improvements

Migration Guide

No migration needed. Users can optionally:

• Use --quiet in scripts for cleaner output
• Rely on automatic directory creation instead of pre-creating paths
• Benefit from more informative status messages automatically

[Copilot]

Pull request overview

This PR addresses critical bugs in header detection and output directory creation, while adding improved status messages and a --quiet flag for better UX and scripting support.

Key Changes

• Fixed header inclusion in content change detection and dry-run previews to prevent incorrect "no change" detection when headers differ
• Added automatic parent directory creation for output paths
• Enhanced status messages with file counts and clearer explanations, plus new --quiet flag for script-friendly output

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
src/core.ts	Fixed content comparison and preview to use finalText (with header) instead of text (without header)
src/fs-safety.ts	Added automatic recursive directory creation in atomicWrite before writing output files
src/cli.ts	Updated status messages with file counts and clarity improvements; added --quiet flag with -q alias
test/core.test.ts	Added header: false to content change test for isolation; added test for nested directory creation
test/cli.test.ts	Updated assertion to match new "Skipped" message format
test/cli-module.test.ts	Updated message assertions and added 3 comprehensive tests for --quiet flag behavior
test/timing-and-backup.test.ts	Updated assertion to match new "Skipped" message format

[Copilot]

Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.

[github-actions]

🎉 This PR is included in version 1.1.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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