Fix syntax highlighting for React/TypeScript files by adding language detection

Co-authored-by: dwjohnston <[email protected]>

Author: Copilot

src/library/GithubPermalink/GithubPermalinkBase.tsx

@@ -6,6 +6,7 @@ import { SyntaxHighlight } from "../SyntaxHighlight/SyntaxHighlight";
 import { formatForLineExclusions } from "./formatLineExclusions";
 import { CopySvg } from "../images/CopySvg";
 import { CopyButton } from "../common/CopyButton/CopyButton";
+import { getLanguageFromPath } from "../utils/getLanguageFromPath";
 
 export type GithubPermalinkBaseProps = {
     className?: string;
@@ -26,6 +27,7 @@ export function GithubPermalinkBase(props: GithubPermalinkBaseProps) {
     if (data.status === "ok") {
 
         const formatedLineExclusions = formatForLineExclusions(data, excludeLines);
+        const language = getLanguageFromPath(data.path);
 
         const clipboard = formatedLineExclusions.reduce((acc, cur) => {
             if (cur.isExclude) {
@@ -41,11 +43,11 @@ export function GithubPermalinkBase(props: GithubPermalinkBaseProps) {
 
             {formatedLineExclusions.map((v) => {
                 if (v.isExclude) {
-                    return <SyntaxHighlight className="hide-line-numbers" text={excludeText} startingLineNumber={v.from} key={v.from}/>
+                    return <SyntaxHighlight className="hide-line-numbers" text={excludeText} startingLineNumber={v.from} language={language} key={v.from}/>
 
                 }
 
-                return <SyntaxHighlight text={v.lines.join("\n")} startingLineNumber={v.from} key={v.from}/>
+                return <SyntaxHighlight text={v.lines.join("\n")} startingLineNumber={v.from} language={language} key={v.from}/>
 
             })}
 

src/library/SyntaxHighlight/SyntaxHighlight.tsx

@@ -131,7 +131,7 @@ export function SyntaxHighlight(props: {
     language?: AvailableLanguagesPrism
 }) {
 
-    const { startingLineNumber, text, className } = props;
+    const { startingLineNumber, text, className, language = "javascript" } = props;
 
     const isDarkMode = useMediaQuery({ query: "(prefers-color-scheme: dark)" })
 

src/library/utils/getLanguageFromPath.test.ts

@@ -0,0 +1,69 @@
+import { describe, it, expect } from 'vitest';
+import { getLanguageFromPath } from './getLanguageFromPath';
+
+describe('getLanguageFromPath', () => {
+    it('should return typescript for .tsx files', () => {
+        expect(getLanguageFromPath('ReactRenders3.tsx')).toBe('typescript');
+    });
+
+    it('should return typescript for .ts files', () => {
+        expect(getLanguageFromPath('component.ts')).toBe('typescript');
+    });
+
+    it('should return javascript for .js files', () => {
+        expect(getLanguageFromPath('script.js')).toBe('javascript');
+    });
+
+    it('should return javascript for .jsx files', () => {
+        expect(getLanguageFromPath('component.jsx')).toBe('javascript');
+    });
+
+    it('should return python for .py files', () => {
+        expect(getLanguageFromPath('script.py')).toBe('python');
+    });
+
+    it('should return go for .go files', () => {
+        expect(getLanguageFromPath('main.go')).toBe('go');
+    });
+
+    it('should return html for .html files', () => {
+        expect(getLanguageFromPath('index.html')).toBe('html');
+    });
+
+    it('should return css for .css files', () => {
+        expect(getLanguageFromPath('styles.css')).toBe('css');
+    });
+
+    it('should return json for .json files', () => {
+        expect(getLanguageFromPath('package.json')).toBe('json');
+    });
+
+    it('should return markdown for .md files', () => {
+        expect(getLanguageFromPath('README.md')).toBe('markdown');
+    });
+
+    it('should return yaml for .yaml files', () => {
+        expect(getLanguageFromPath('config.yaml')).toBe('yaml');
+    });
+
+    it('should return yaml for .yml files', () => {
+        expect(getLanguageFromPath('config.yml')).toBe('yaml');
+    });
+
+    it('should return javascript as fallback for unknown extensions', () => {
+        expect(getLanguageFromPath('file.unknown')).toBe('javascript');
+    });
+
+    it('should return javascript as fallback for files without extension', () => {
+        expect(getLanguageFromPath('README')).toBe('javascript');
+    });
+
+    it('should handle paths with multiple dots', () => {
+        expect(getLanguageFromPath('src/components/MyComponent.tsx')).toBe('typescript');
+    });
+
+    it('should handle case insensitive extensions', () => {
+        expect(getLanguageFromPath('Component.TSX')).toBe('typescript');
+        expect(getLanguageFromPath('Script.JS')).toBe('javascript');
+    });
+});

src/library/utils/getLanguageFromPath.ts

@@ -0,0 +1,90 @@
+import { AvailableLanguagesPrism } from "../SyntaxHighlight/availableLanguagesPrism";
+
+/**
+ * Maps file extensions to syntax highlighting languages supported by react-syntax-highlighter
+ */
+export function getLanguageFromPath(filePath: string): AvailableLanguagesPrism {
+    const extension = filePath.split('.').pop()?.toLowerCase();
+
+    switch (extension) {
+        case 'js':
+        case 'jsx':
+        case 'mjs':
+        case 'cjs':
+            return 'javascript';
+        case 'ts':
+        case 'tsx':
+            return 'typescript';
+        case 'py':
+        case 'python':
+            return 'python';
+        case 'java':
+            return 'java';
+        case 'cpp':
+        case 'cc':
+        case 'cxx':
+        case 'c++':
+            return 'cpp';
+        case 'c':
+        case 'h':
+            return 'c';
+        case 'cs':
+            return 'csharp';
+        case 'php':
+            return 'php';
+        case 'rb':
+        case 'ruby':
+            return 'ruby';
+        case 'go':
+            return 'go';
+        case 'rs':
+            return 'rust';
+        case 'swift':
+            return 'swift';
+        case 'kt':
+        case 'kts':
+            return 'kotlin';
+        case 'scala':
+            return 'scala';
+        case 'sh':
+        case 'bash':
+            return 'bash';
+        case 'ps1':
+            return 'powershell';
+        case 'sql':
+            return 'sql';
+        case 'html':
+        case 'htm':
+            return 'html';
+        case 'css':
+            return 'css';
+        case 'scss':
+        case 'sass':
+            return 'scss';
+        case 'json':
+            return 'json';
+        case 'xml':
+            return 'xml';
+        case 'yaml':
+        case 'yml':
+            return 'yaml';
+        case 'md':
+        case 'markdown':
+            return 'markdown';
+        case 'dockerfile':
+            return 'dockerfile';
+        case 'r':
+            return 'r';
+        case 'dart':
+            return 'dart';
+        case 'lua':
+            return 'lua';
+        case 'perl':
+        case 'pl':
+            return 'perl';
+        case 'vim':
+            return 'vim';
+        default:
+            return 'javascript'; // fallback to javascript for unknown extensions
+    }
+}