TextHighlighter

A flexible React component for highlighting specific words or phrases within text content or React components.

Features

• 🎯 Flexible Input: Works with both plain text and React components
• 🔍 Multiple Words: Highlight single words, arrays of words, regex patterns, or arrays of regex patterns
• 🎨 Custom Styling: Fully customizable highlight styles
• 📝 Case Sensitivity: Optional case-sensitive or case-insensitive matching
• 🔧 TypeScript Support: Written in TypeScript with proper type definitions
• 🚀 Zero Dependencies: Uses only React built-in functionality
• 🌳 Deep Processing: Recursively processes nested React components

Installation

npm	yarn	pnpm *
npm install react-highlight-me	yarn add react-highlight-me	pnpm add react-highlight-me

*) pnpm is a preferable package manager for me at the moment.

Usage

Basic Text Highlighting

import TextHighlighter from 'react-highlight-me';

function App() {
  return (
    <TextHighlighter words="React">
      Hello React world!
    </TextHighlighter>
  );
}

Multiple Words

<TextHighlighter 
  words={['React', 'TypeScript', 'JavaScript']}
  highlightStyle={{ backgroundColor: '#fef3c7', padding: '2px 4px' }}
>
  Learning React and TypeScript for JavaScript development
</TextHighlighter>

Component Highlighting

<TextHighlighter 
  words={['important', 'notice']}
  highlightStyle={{ backgroundColor: '#fca5a5', fontWeight: 'bold' }}
>
  <div>
    <h2>Important Notice</h2>
    <p>This is an important message about our service.</p>
    <ul>
      <li>First important point</li>
      <li>Another notice for users</li>
    </ul>
  </div>
</TextHighlighter>

Custom Styling

// Yellow background with rounded corners
<TextHighlighter 
  words="highlight"
  highlightStyle={{ 
    backgroundColor: 'yellow',
    padding: '2px 6px',
    borderRadius: '4px',
    fontWeight: 'bold'
  }}
>
  Text to highlight here
</TextHighlighter>

// Blue background with white text
<TextHighlighter 
  words="special"
  highlightStyle={{ 
    backgroundColor: '#3b82f6',
    color: 'white',
    padding: '3px 8px',
    borderRadius: '6px'
  }}
>
  This is special content
</TextHighlighter>

// Border style instead of background
<TextHighlighter 
  words="outlined"
  highlightStyle={{ 
    backgroundColor: 'transparent',
    border: '2px solid #10b981',
    padding: '1px 4px',
    borderRadius: '4px',
    color: '#059669',
    fontWeight: 'bold'
  }}
>
  Text with outlined highlights
</TextHighlighter>

Case Sensitivity

// Case-insensitive (default)
<TextHighlighter words="react">
  REACT and React and react will all be highlighted
</TextHighlighter>

// Case-sensitive
<TextHighlighter words="React" caseSensitive={true}>
  Only React will be highlighted, not REACT or react
</TextHighlighter>

Gettting highlighted words

import TextHighlighter from 'react-highlight-me';
function App() {
  const highlightedWords = ['React', 'JavaScript'];

  return (
    <>
      <TextHighlighter words={highlightedWords}>
        <div>
          React is a JavaScript library for building user interfaces.
        </div>
      </TextHighlighter>
      <div>
        <h2>Highlighted Words:</h2>
        <ul>
          {Array.from(document.querySelectorAll(TextHighlighter.MARKS_IN_SCOPE_SELECTOR)).map((mark, index) => (
            <li key={index}>{mark.textContent}</li>
          ))}
        </ul>
      </div>
    </>
  );
}

Props

Prop	Type	Default	Description
children	React.ReactElement | null	''	The content to process for highlighting
words	string[] | string | RegExp | RegExp[]	[]	Word or array of words to highlight
highlightStyle	React.CSSProperties	{ backgroundColor: 'yellow', fontWeight: 'bold' }	CSS styles to apply to highlighted text
caseSensitive	boolean	false	Whether to perform case-sensitive matching
isWordBoundary	boolean	false	Match words only at word boundaries
escapeRegex	RegExp	/[.*+?^${}()|[\]\\]/g	Escape special regex characters

Examples

Search Results Highlighting

function SearchResults({ results, searchTerm }) {
  return (
    <div>
      {results.map((result, index) => (
        <div key={index} className="search-result">
          <TextHighlighter 
            words={searchTerm}
            highlightStyle={{ backgroundColor: '#fbbf24' }}
          >
            <div>
              <h3>{result.title}</h3>
              <p>{result.description}</p>
            </div>
          </TextHighlighter>
        </div>
      ))}
    </div>
  );
}

Documentation Highlighting

function Documentation({ content, keywords }) {
  return (
    <TextHighlighter 
      words={keywords}
      highlightStyle={{ 
        backgroundColor: '#ddd6fe',
        padding: '2px 4px',
        borderRadius: '3px',
        fontWeight: 'bold'
      }}
    >
      <article>
        <h1>API Documentation</h1>
        <p>{content}</p>
      </article>
    </TextHighlighter>
  );
}

Multi-language Support

function MultiLanguageHighlight() {
  return (
    <TextHighlighter 
      words={['JavaScript', 'React', 'TypeScript']}
      highlightStyle={{ backgroundColor: '#c7d2fe' }}
    >
      <div>
        <p>JavaScript is a programming language</p>
        <p>React est une bibliothèque JavaScript</p>
        <p>TypeScript adds static typing to JavaScript</p>
      </div>
    </TextHighlighter>
  );
}

Technical Details

How It Works

1. Text Processing: The component recursively traverses React elements and their children
2. Pattern Matching: Uses regular expressions to find and match specified words
3. Safe Rendering: Escapes regex special characters to prevent injection issues
4. Element Cloning: Preserves original component structure while adding highlights

Performance Considerations

• The component processes content recursively, so very deep component trees may impact performance
• Regex compilation happens on each render - consider memoization for frequently changing props
• Large amounts of text with many highlight words may benefit from virtualization

Browser Support

Works in all modern browsers that support:

• React 16.8+
• ES6 Regular Expressions
• Array methods (map, filter, some)

Development & Debugging

This package includes TypeScript source files for easier debugging and development:

// For production (compiled):
import { Highlighter } from 'react-highlight-me';

// For debugging (source):
import { Highlighter } from 'react-highlight-me/src';

Source maps are included to map compiled code back to TypeScript sources in your debugger.

Contributing

Feel free to submit issues, feature requests, or pull requests to improve the component.

License

ISC License - see LICENSE file for details.