React Compare

A React component for comparing strings and arrays with precise word-level and item-level highlighting of differences.

Live Demos

Interactive Storybook

👉 Live Storybook Demo

Explore and interact with all features of this component. Adjust inputs and props using the controls panel to see how the component behaves with different data.

Test Coverage Report

📊 View Coverage Report

Detailed test coverage metrics showing 99.31% statement coverage, 94.39% branch coverage, and 100% function coverage.

Features

• 🎯 Precise Highlighting: Only highlights the actual differences, not entire lines
• 📝 String Comparison: Word-level diff for text content
• 📋 Array Comparison: Item-level diff for arrays of strings
• 📄 Contentful Rich Text: Compare Contentful documents with text or structure modes
• 🎨 Clean Visual Design: Clear red/green highlighting for changes
• 📱 Responsive: Works on desktop and mobile devices
• ⚡ TypeScript Support: Full TypeScript definitions included
• 🎛️ Multiple Views: Side-by-side or inline comparison modes
• ✅ Comprehensive Testing: 80%+ test coverage with 114+ test scenarios

Installation

npm install @crashbytes/react-version-compare

yarn add @crashbytes/react-version-compare

Basic Usage

String Comparison

import React from 'react';
import Compare from '@crashbytes/react-version-compare';
import '@crashbytes/react-version-compare/dist/styles.css';

const App = () => {
  const original = 'I am Captain Kirk, Captain of the USS Enterprise.';
  const modified = 'I am Captain Picard, Captain of the USS Enterprise.';

  return (
    <Compare 
      original={original}
      modified={modified}
    />
  );
};

Result: Only "Kirk" (in red) and "Picard" (in green) will be highlighted.

Array Comparison

const originalArray = [
  'First item',
  'Second item', 
  'Third item'
];

const modifiedArray = [
  'First item',
  'Modified second item',
  'Third item'
];

<Compare 
  original={originalArray}
  modified={modifiedArray}
/>

Contentful Rich Text Comparison

The component now supports comparing Contentful Rich Text documents with two different modes:

import { Compare } from '@crashbytes/react-version-compare';
import { Document } from '@contentful/rich-text-types';

// Text mode - extracts plain text for comparison
<Compare 
  original={contentfulDoc1}
  modified={contentfulDoc2}
  compareMode="text"
  viewMode="side-by-side"
/>

// Structure mode - compares document structure
<Compare 
  original={contentfulDoc1}
  modified={contentfulDoc2}
  compareMode="structure"
  viewMode="side-by-side"
/>

Structure Mode preserves the semantic meaning of the document by comparing:

• Headings (with levels)
• Paragraphs
• Lists and list items
• Block quotes
• And other rich text elements

Text Mode extracts plain text content and performs word-level comparison, similar to string comparison.

API Reference

Props

Prop	Type	Default	Description
original	string | string[] | Document	required	The original content
modified	string | string[] | Document	required	The modified content
viewMode	'side-by-side' | 'inline'	'side-by-side'	How to display the comparison
className	string	''	Custom CSS class name
caseSensitive	boolean	true	Whether comparison is case sensitive
compareMode	'text' | 'structure'	'text'	Comparison mode for Contentful documents

Examples

Precise Word-Level Highlighting

// Example 1: Minimal changes
const original = 'I am Captain Kirk, Captain of the USS Enterprise.';
const modified = 'I am Captain Picard, Captain of the USS Enterprise.';
// Only "Kirk" → "Picard" highlighted

// Example 2: Multiple changes  
const original = 'I am Captain Kirk, Captain of the USS Enterprise.';
const modified = 'I am Commander Benjamin Sisko, Commander of Deep Space 9.';
// Highlights: "Captain Kirk, Captain of the USS Enterprise" → "Commander Benjamin Sisko, Commander of Deep Space 9"

Array Comparison

const original = ['Item A', 'Item B', 'Item C'];
const modified = ['Item A', 'Modified Item B', 'Item C', 'Item D'];

<Compare original={original} modified={modified} />

Inline View

<Compare 
  original="Original text"
  modified="Modified text"
  viewMode="inline"
/>

Testing

This package includes comprehensive unit and integration tests with 80%+ coverage.

Running Tests

# Run all tests
npm test

# Run tests with coverage report
npm run test:coverage

# Run tests in watch mode (for development)
npm run test:watch

# Run specific test file
npm test -- Compare.enhanced.test.tsx

Test Coverage

The test suite includes:

• 114+ test scenarios covering edge cases and real-world usage
• Unit tests: Component logic, utility functions, type guards
• Integration tests: Real-world scenarios (code snippets, JSON, SQL, URLs)
• Edge case tests: Empty inputs, null/undefined, large datasets, unicode
• Accessibility tests: Semantic structure, screen reader support
• Performance tests: Large arrays (100+ items), large strings (1000+ words)

Coverage thresholds enforced by Jest:

• Branches: 75%
• Functions: 80%
• Lines: 80%
• Statements: 80%

See TEST-COVERAGE-SUMMARY.md for detailed test documentation.

Test Files

__tests__/
├── Compare.test.tsx                    # Original basic tests
├── Compare.enhanced.test.tsx           # Edge cases & comprehensive coverage
├── Compare.integration.test.tsx        # Real-world scenarios
├── ContentfulDiff.test.tsx             # Original utility tests
└── ContentfulDiff.enhanced.test.tsx    # Complete utility coverage

Styling

The component uses CSS classes that you can customize:

.diff-removed {
  /* Styling for removed content (red) */
}

.diff-added {
  /* Styling for added content (green) */
}

.diff-unchanged {
  /* Styling for unchanged content */
}

Use Cases

• Document revisions: Compare different versions of text
• Code reviews: Highlight changes in code snippets
• Content management: Show edits in articles or posts
• Data comparison: Compare lists or arrays of items
• Translation work: Compare original and translated text
• Contentful CMS: Compare rich text content versions and track editorial changes
• Documentation: Track changes in structured content with semantic meaning

How It Works

• String comparison: Uses word-level diffing to identify precise changes
• Array comparison: Compares items by position and content
• Contentful comparison: Extracts plain text or compares structural elements
• Smart highlighting: Only highlights actual differences, not entire lines
• Type safety: Ensures both inputs are the same type (strings, arrays, or Contentful documents)

License

Apache License 2.0 - see the LICENSE file for details.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Development Setup

# Install dependencies
npm install

# Run tests
npm test

# Run tests with coverage
npm run test:coverage

# Build the package
npm run build

# Run Storybook for local development
npm run storybook

Support

If you encounter any issues or have questions, please open an issue on GitHub.

Changelog

See CHANGELOG.md for release history.

Versioning

To bump the version, use npm version:

npm version patch   # or 'minor' or 'major'

This will update package.json, create a git tag, and (optionally) commit the change.