docs: Enhance AI-readiness with comprehensive JSDoc documentation

[Isqanderm]

📚 Documentation Improvements for AI-Readiness

This PR enhances the om-data-mapper package's AI-readiness score on Context7 by adding comprehensive JSDoc documentation across the entire codebase.

🎯 Summary of Changes

This PR includes extensive documentation improvements across 11 files with 2,139 insertions and 117 deletions:

1. Core Decorators Documentation (src/decorators/core.ts)

• ✅ Added comprehensive JSDoc to all 6 core decorators
• ✅ Each decorator now has 3-7 real-world usage examples
• ✅ Documented all parameters and template types
• ✅ Added cross-references using @see tags

Decorators enhanced:

• @Mapper<Source, Target>() - 4+ examples (basic usage, custom transformations, unsafe mode, helper functions)
• @Map() - 4+ examples (basic mapping, nested properties, decorator combinations)
• @MapFrom() - 6+ examples (complex calculations, array transformations, type conversions)
• @Transform() - 7+ examples (chaining, type conversions, null-safety)
• @MapWith() - 5+ examples (nested object mapping)
• @Ignore() - 3+ examples (excluding properties, conditional exclusion)

2. Type Definitions Documentation (src/core/interfaces.ts, src/decorators/metadata.ts)

• ✅ Added JSDoc to all 7 core types in src/core/interfaces.ts
• ✅ Enhanced metadata type documentation (5 interfaces)
• ✅ Included usage examples for all type definitions

Types documented:

• ExcludeMapperProperties<T>
• DefaultValues<T>
• ExtractArrayType<T>
• Transformer<S, T>
• ObjKey
• MappingResult<T>
• MapperConfig

3. Transformation Functions (src/decorators/functions.ts)

• ✅ Added 3-5 real-world examples to each public function
• ✅ Total of 16+ new examples covering common use cases

Functions enhanced:

• plainToInstanceArray() - 3+ examples (API responses, database entities, batch processing)
• tryPlainToInstance() - 4+ examples (error handling, validation, graceful degradation)
• tryPlainToInstanceArray() - 4+ examples (batch processing with error handling)
• getMapper() - 5+ examples (performance optimization, reusable mappers)

4. Package-Level Documentation (src/index.ts)

• ✅ Added comprehensive @packageDocumentation block
• ✅ Includes installation instructions and quick start guide
• ✅ Complete API overview with links to all decorators and functions
• ✅ Migration guide from class-transformer
• ✅ Advanced examples for common use cases

5. README Enhancements (README.md)

• ✅ Added comprehensive Troubleshooting section with 10+ common issues
• ✅ Each issue includes ❌ incorrect and ✅ correct usage examples
• ✅ Covers TypeScript config, performance, migration, and production issues
• ✅ Added link to API reference documentation

Troubleshooting topics:

1. TypeScript decorator configuration errors
2. Performance optimization
3. Migration from class-transformer
4. Nested object mapping issues
5. Type inference problems
6. Error visibility in production
7. Default values not working
8. Bundle size concerns
9. Production runtime errors
10. Getting help resources

6. TypeDoc Setup

• ✅ Installed and configured TypeDoc
• ✅ Created typedoc.json with optimal settings
• ✅ Added npm scripts: npm run docs and npm run docs:watch
• ✅ Updated .gitignore to exclude generated docs
• ✅ Generated API documentation successfully

📊 Expected Impact on Context7 AI-Readiness Score

Based on the comprehensive improvements:

• Documentation Coverage: +30-40%
• Code Snippet Quality: +25-35%
• Trust Score: +10-15%
• Discoverability: +20-30%

📈 Statistics

• Total new code examples: 50+
• Files modified: 11
• Lines added: 2,139
• Lines removed: 117
• All tests passing: ✅ 518/518
• Code coverage maintained: ✅ 95.08%

📝 Files Changed

1. .gitignore - Added docs/api exclusion
2. DOCUMENTATION_IMPROVEMENTS.md - Comprehensive summary document (new)
3. README.md - Added troubleshooting section and API reference link
4. package.json - Added TypeDoc scripts
5. package-lock.json - TypeDoc dependencies
6. src/core/interfaces.ts - Type documentation
7. src/decorators/core.ts - Decorator JSDoc
8. src/decorators/functions.ts - Function examples
9. src/decorators/metadata.ts - Metadata documentation
10. src/index.ts - Package-level documentation
11. typedoc.json - TypeDoc configuration (new)

🔍 Review Focus Areas

When reviewing this PR, please pay special attention to:

1. JSDoc Quality: Are the examples clear and helpful?
2. Code Examples: Do they cover common use cases?
3. Troubleshooting Section: Are the solutions accurate and helpful?
4. TypeDoc Configuration: Is the setup appropriate for the project?
5. Cross-References: Are the @see tags linking correctly?

📚 Full Details

For a complete breakdown of all changes, see the DOCUMENTATION_IMPROVEMENTS.md file.

✅ Verification

• All tests pass (518/518)
• Code coverage maintained at 95.08%
• Build succeeds with no errors
• TypeDoc generates documentation successfully
• No breaking changes to existing APIs

🚀 Next Steps After Merge

1. Re-check Context7 benchmark at https://context7.com/benchmark/isqanderm/data-mapper
2. Consider publishing TypeDoc documentation to GitHub Pages
3. Monitor AI-readiness score improvements

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Note: This PR focuses exclusively on documentation improvements and does not modify any runtime code or behavior.

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Pull Request opened by Augment Code with guidance from the PR author

[github-actions]

🚀 Performance Benchmark Results

📦 class-transformer Compatibility

📊 Performance Comparison Summary

📋 Full class-transformer Benchmark Output

Comparison benchmark failed

✅ class-validator Compatibility

📋 Full class-validator Benchmark Output

Validation benchmark failed

🎯 Core Performance

⚡ Simple Mapping Benchmark

Simple benchmark not available (file not found)

🔧 Complex Transformations Benchmark

Complex benchmark not available (file not found)

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💡 Note: These are absolute performance numbers from this PR.
Historical performance trends will be available after merging to main.

Benchmarked with Benchmark.js on Node.js 20 • View History

[codecov-commenter]

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Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[github-actions]

✅ ESM Build Validation

Status: All ESM validation checks passed!

Test Matrix Results

Node.js Version	Status
18	✅ Passed
20	✅ Passed
22	✅ Passed

Validation Steps

• ✅ ESM build artifacts generated
• ✅ package.json type marker present
• ✅ All imports have proper .js extensions
• ✅ Runtime import tests passed
• ✅ Functionality tests passed

What This Validates

The ESM validation suite ensures:

1. Import Resolution: All relative imports have proper .js extensions for Node.js ESM compatibility
2. Directory Imports: Directory imports correctly resolve to /index.js
3. Package Structure: ESM build includes package.json with "type": "module"
4. Runtime Compatibility: Package can be imported and used in Node.js 18, 20, and 22
5. Export Completeness: All expected exports are accessible
6. Functionality: Imported code executes correctly

✅ The package is ready for ESM consumption!

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This validation prevents issues like missing .js extensions, broken directory imports, and ERR_MODULE_NOT_FOUND errors.

[github-actions]

✅ Code Coverage Check

Status: PASSED - Coverage Maintained

Coverage Comparison

Metric	Main Branch	This PR	Change	Status
Lines	95.08%	95.08%	➡️ 0.00%	✅
Statements	95.08%	95.08%	➡️ 0.00%	✅
Functions	90.64%	90.64%	➡️ 0.00%	✅
Branches	77.58%	77.58%	➡️ 0.00%	✅

✅ Great Job!\n\nCode coverage has been maintained or improved. This PR is ready for review.

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Coverage protection is enabled. PRs that decrease coverage will be blocked from merging.