Overview
The Diff component parses + and - symbols on the head of lines,
and highlights them as added/deleted lines.
export default function Layout( { children } ) {
  return (
-   <div>
-     { children }
-   </div>
+   <main className={ styles.main }>
+     <section>{ children }</section>
+   </main>
  );
}
      This works with the LineNumbers component:
export default function Layout( { children } ) {
  return (
-   <div>
-     { children }
-   </div>
+   <main className={ styles.main }>
+     <section>{ children }</section>
+   </main>
  );
}
      Usage
Register the Gutter and Diff components:
import { RyuseiLight, Gutter, Diff } from '@ryusei/light';
RyuseiLight.compose( { Gutter, Diff } );
// Register LineNumbers if necessary.
// RyuseiLight.compose( { Gutter, Diff, LineNumbers } );
      Or import the component files:
<script src="path-to-the-file/gutter.min.js"></script> <script src="path-to-the-file/diff.min.js"></script> <!-- Import line-numbers.min.js if necessary --> <!--<script src="path-to-the-file/line-numbers.min.js"></script>-->
Next, prepend + for added lines and/or - for removed ones to your snippet:
<pre>
export default function Layout( { children } ) {
  return (
-   <div>
-     { children }
-   </div>
+   <main className={ styles.main }>
+     <section>{ children }</section>
+   </main>
  );
}
</pre>
      Then, set the diff option to true:
ryuseilight.apply( 'pre', { diff: true } );
      Options
The Diff component accepts some options by providing an object literal instead of true.
| Option | Description | 
|---|---|
| removeSymbols | Whether to remove +/-symbols or convert them to a space. | 
| addedSymbol | Determines a symbol for added lines. The default value is +. | 
| deletedSymbol | Determines a symbol for deleted (removed) lines. The default value is -. | 
By default, the Diff component converts + and - to spaces.
You can remove them by setting removeSymbols to true.
Also, the default symbols can be changed by addedSymbol and deletedSymbol options:
ryuseilight.apply( 'pre', { 
  diff: {
    addedSymbol  : '>',
    deletedSymbol: '<',
  },
} );