Feature/typescript type inference

[yasserfedsi]

Pull Request

Summary

This release introduces major TypeScript improvements to envfy, making the library fully type-safe while preserving its simple runtime API.

The focus of this release is improving the developer experience through automatic type inference and a cleaner public API.

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Motivation

Before this release, validateEnv() correctly validated environment variables at runtime, but the returned object lacked accurate TypeScript inference.

This update allows editors to automatically infer:

• Primitive types
• Enum literal values
• Optional properties
• Properties with default values

without requiring users to write any additional interfaces or type assertions.

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Related Issues

Closes #N/A

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Type of Change

• Bug fix
• New feature
• Breaking change
• Refactor
• Documentation update
• Performance improvement
• Tests
• CI/CD

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Changes Made

TypeScript

• Added generic validateEnv<T>().
• Added automatic schema type inference.
• Added primitive type inference.
• Added enum literal type inference.
• Added optional property inference.
• Added default value inference.
• Improved exported public types.
• Refactored shared type definitions.

Documentation

• Updated README with:
  • Type inference examples
  • Default value examples
  • Improved feature overview
  • Better API documentation
• Updated CHANGELOG for v0.6.0.

Developer Experience

• Improved IntelliSense support.
• Cleaner public API exports.
• Better editor autocomplete.

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Testing

Automated

• Existing unit tests pass.
• Enum validation verified.
• Optional variable validation verified.
• Default value validation verified.

Manual

Verified by creating a sample project and testing:

• Valid environment variables.
• Invalid primitive values.
• Invalid enum values.
• Missing required variables.
• Optional variables.
• Default values.
• TypeScript inference inside VS Code.

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Breaking Changes

• No breaking changes.

All existing runtime behavior remains compatible.

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Documentation

• README updated.
• CHANGELOG updated.
• Public API examples updated.

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Checklist

• Code follows the project's coding standards.
• Self-review completed.
• Existing tests pass.
• Documentation updated.
• No unnecessary dependencies introduced.
• Ready for review.

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Additional Notes

This release focuses on developer experience rather than runtime functionality.

With automatic TypeScript inference now supported, envfy provides a more intuitive and type-safe API while maintaining zero runtime dependencies and a lightweight footprint.