React Content Highlighting Strategies: Code vs. Text

When building React applications, you often need to highlight content for better readability. However, not all highlighting packages serve the same purpose. react-highlight and react-syntax-highlighter focus on code syntax, while react-highlight-words targets plain text search terms. Understanding these differences is critical for architectural decisions.

🎯 Core Purpose: Code Syntax vs. Search Terms

The most important distinction lies in what each package is designed to highlight. Using a code highlighter for text search is inefficient, and using a text highlighter for code ignores syntax rules.

react-highlight is built for code syntax using Highlight.js.

• It analyzes code strings and applies classes based on language grammar.
• Best for displaying snippets in blogs or documentation.

// react-highlight: Code syntax
import Highlight from 'react-highlight';

function CodeBlock() {
  return (
    <Highlight className="javascript">
      {`console.log("Hello World");`}
    </Highlight>
  );
}

react-syntax-highlighter is also for code syntax but supports multiple engines.

• It allows switching between Prism and Highlight.js.
• Offers more control over rendering and features.

// react-syntax-highlighter: Code syntax
import { Prism as SyntaxHighlighter } from 'react-syntax-highlighter';

function CodeBlock() {
  return (
    <SyntaxHighlighter language="javascript">
      {`console.log("Hello World");`}
    </SyntaxHighlighter>
  );
}

react-highlight-words is built for plain text search terms.

• It does not understand code syntax or languages.
• It highlights specific substrings within a text block.

// react-highlight-words: Text search
import Highlighter from 'react-highlight-words';

function SearchResults() {
  return (
    <Highlighter
      searchWords={['Hello']}
      textToHighlight="Hello World"
    />
  );
}

🎨 Styling and Themes

How you apply styles varies significantly between code highlighters and text highlighters. Code highlighters often rely on pre-built themes, while text highlighters require custom CSS for match tags.

react-highlight uses Highlight.js themes via CSS imports.

• You import a CSS file provided by the library.
• Limited to available Highlight.js themes.

// react-highlight: Theme import
import 'highlight.js/styles/github.css';

// Usage automatically picks up the CSS
<Highlight className="javascript">{code}</Highlight>

react-syntax-highlighter supports dynamic theme switching.

• You pass the theme as a prop.
• Easier to allow users to toggle between light and dark modes.

// react-syntax-highlighter: Dynamic theme
import { docco } from 'react-syntax-highlighter/dist/esm/styles/hljs';

<SyntaxHighlighter language="javascript" style={docco}>
  {code}
</SyntaxHighlighter>

react-highlight-words requires custom CSS for highlights.

• You define how the highlighted text looks using highlightStyle.
• Gives full control over background, color, and padding.

// react-highlight-words: Custom style
<Highlighter
  searchWords={['term']}
  textToHighlight="Some text with term"
  highlightStyle={{ backgroundColor: 'yellow', color: 'black' }}
/>

⚙️ Configuration and Features

Feature sets differ based on the complexity of the highlighting task. Code highlighters need language detection and line numbers, while text highlighters need case sensitivity controls.

react-highlight offers basic configuration.

• Primarily relies on className for language detection.
• Lacks built-in line numbers or custom token rendering.

// react-highlight: Basic config
<Highlight className="python">{code}</Highlight>
// No built-in prop for line numbers

react-syntax-highlighter provides advanced features.

• Supports line numbers, starting line index, and custom renderers.
• Allows fine-tuning of code block behavior.

// react-syntax-highlighter: Advanced config
<SyntaxHighlighter
  language="python"
  showLineNumbers={true}
  startingLineNumber={10}
>
  {code}
</SyntaxHighlighter>

react-highlight-words focuses on text matching options.

• Controls case sensitivity and match boundaries.
• Allows custom rendering of highlight tags.

// react-highlight-words: Match options
<Highlighter
  searchWords={['term']}
  textToHighlight="Term and term"
  caseSensitive={false}
  highlightTag="span"
/>

🛠️ Customization and Extensibility

When default behavior isn't enough, each package offers different extension points. Code highlighters allow custom token styling, while text highlighters allow custom match components.

react-highlight has limited customization.

• You must override CSS classes to change token colors.
• Harder to inject custom components into the code flow.

// react-highlight: CSS override
/* In your CSS file */
.hljs-keyword {
  color: blue !important;
}

react-syntax-highlighter allows custom renderers.

• You can replace default elements with custom components.
• Useful for adding copy buttons or interactive elements.

// react-syntax-highlighter: Custom renderer
<SyntaxHighlighter
  language="javascript"
  customStyle={{ background: '#f0f0f0' }}
>
  {code}
</SyntaxHighlighter>

react-highlight-words allows custom highlight components.

• You can pass a component to render matches.
• Enables adding icons or tooltips to highlighted words.

// react-highlight-words: Custom component
<Highlighter
  searchWords={['term']}
  textToHighlight="text"
  highlightTag={({ children, ...rest }) => (
    <span {...rest} className="custom-highlight">{children}</span>
  )}
/>

📊 Summary: Key Differences

💡 Final Recommendation

react-highlight is suitable for simple projects where you just need to display code with minimal setup. It works well if you are already using Highlight.js elsewhere and want a quick React wrapper.

react-syntax-highlighter is the standard choice for modern React applications requiring code display. Its support for multiple engines, line numbers, and dynamic themes makes it the most flexible option for documentation and developer tools.

react-highlight-words is the only choice for highlighting search terms in plain text. Do not attempt to use code highlighters for this task, as they will not match substrings correctly. Use this for search result pages or content filters.

Final Thought: Always match the tool to the content type. Use code highlighters for code blocks and text highlighters for user-generated content or search results. Mixing them leads to poor performance and incorrect rendering.