Add Extended Text Extraction and Enhanced Filtering Features

[KhaliLounis]

Summary

This PR introduces two new features that significantly expand the tool's capabilities beyond JSX text extraction, making it more comprehensive for real-world i18n workflows.

Features Added

1. Non-Alphabetic Character Filtering (--filter-non-alpha)

Filters out text containing only non-alphabetic characters (symbols, numbers, emojis) to reduce noise in extraction output.

Use Case: Prevents extraction of standalone symbols like $, single letters, or number-only strings that aren't meaningful for translation.

Example:

# Before:
[ProductCard.tsx:30] $
[ProductCard.tsx:33] In Stock

# With --filter-non-alpha:
[ProductCard.tsx:33] In Stock  # $ is filtered out

2. Extended Literal Extraction (--include-literals)

Extracts user-facing strings from sources beyond JSX, including:

Object Properties

Extracts strings from objects with user-facing keys like message, error, label, title, description, etc.

Zod Schema Validation Messages

Supports all common Zod validation patterns:

Function Calls

Extracts from common user-facing function calls:

Advanced Filtering

The tool now automatically skips technical strings to prevent false positives:

• Import paths and URLs, CSS class names and IDs, camelCase identifiers and CONSTANTS, Single characters and code-like patterns.

Performance Impact

Testing on the example codebase shows significant improvement:

• Without --include-literals: 73 strings extracted (JSX only)
• With --include-literals: 98 strings extracted

Changes

Core Implementation

• Added --filter-non-alpha / -f flag with character validation
• Added --include-literals / -l flag with AST traversal for:
  • ObjectProperty nodes (with advanced key filtering)
  • NewExpression nodes (Error constructors)
  • CallExpression nodes (toast, console, Zod methods)
• Implemented isUserFacingText() function to filter technical strings
• Added configurable sets for user-facing keys, functions, and skip patterns

Documentation

• Updated README with comprehensive examples
• Added "What it extracts" section with detailed code samples
• Clarified npm script usage with -- separator
• Added example output comparisons

Testing

• Added example/src/test-literals.tsx with comprehensive test cases
• Renamed example/src/App.tsx to App.jsx to demonstrate the --ext flag usage with JavaScript files