feat(theme-classic): usable CodeBlock outside markdown (#6216)

packages/docusaurus-theme-classic/src/theme-classic.d.ts

@@ -114,6 +114,7 @@ declare module '@theme/CodeBlock' {
     readonly className?: string;
     readonly metastring?: string;
     readonly title?: string;
+    readonly language?: string;
   }
 
   const CodeBlock: (props: Props) => JSX.Element;

packages/docusaurus-theme-classic/src/theme/CodeBlock/index.tsx

@@ -24,9 +24,10 @@ import styles from './styles.module.css';
 
 export default function CodeBlock({
   children,
-  className: blockClassName,
+  className: blockClassName = '',
   metastring,
   title,
+  language: languageProp,
 }: Props): JSX.Element {
   const {prism} = useThemeConfig();
 
@@ -85,8 +86,7 @@ export default function CodeBlock({
     : (children as string);
 
   const language =
-    parseLanguage(blockClassName) ??
+    languageProp ?? parseLanguage(blockClassName) ?? prism.defaultLanguage;
-    (prism.defaultLanguage as Language | undefined);
   const {highlightLines, code} = parseLines(content, metastring, language);
 
   const handleCopyCode = () => {
@@ -102,12 +102,16 @@ export default function CodeBlock({
       key={String(mounted)}
       theme={prismTheme}
       code={code}
-      language={language ?? ('text' as Language)}>
+      language={(language ?? 'text') as Language}>
       {({className, style, tokens, getLineProps, getTokenProps}) => (
         <div
           className={clsx(
             styles.codeBlockContainer,
             blockClassName,
+            {
+              [`language-${language}`]:
+                language && !blockClassName.includes(`language-${language}`),
+            },
             ThemeClassNames.common.codeBlock,
           )}>
           {codeBlockTitle && (

packages/docusaurus-theme-common/src/utils/codeBlockUtils.ts

@@ -6,7 +6,6 @@
  */
 
 import rangeParser from 'parse-numeric-range';
-import type {Language} from 'prism-react-renderer';
 
 const codeBlockTitleRegex = /title=(["'])(.*?)\1/;
 const highlightLinesRangeRegex = /{([\d,-]+)}/;
@@ -93,11 +92,11 @@ export function parseCodeBlockTitle(metastring?: string): string {
   return metastring?.match(codeBlockTitleRegex)?.[2] ?? '';
 }
 
-export function parseLanguage(className?: string): Language | undefined {
+export function parseLanguage(className: string): string | undefined {
   const languageClassName = className
-    ?.split(' ')
+    .split(' ')
     .find((str) => str.startsWith('language-'));
-  return languageClassName?.replace(/language-/, '') as Language | undefined;
+  return languageClassName?.replace(/language-/, '');
 }
 
 /**
@@ -107,7 +106,7 @@ export function parseLanguage(className?: string): Language | undefined {
 export function parseLines(
   content: string,
   metastring?: string,
-  language?: Language,
+  language?: string,
 ): {
   highlightLines: number[];
   code: string;

website/docs/guides/markdown-features/markdown-features-code-blocks.mdx

@@ -6,6 +6,7 @@ slug: /markdown-features/code-blocks
 ---
 
 import BrowserWindow from '@site/src/components/BrowserWindow';
+import CodeBlock from '@theme/CodeBlock';
 
 Code blocks within documentation are super-powered 💪.
 
@@ -391,7 +392,7 @@ function MyPlayground(props) {
 
 </BrowserWindow>
 
-## Using JSX markup in code blocks
+## Using JSX markup in code blocks {using-jsx-markup}
 
 Code block in Markdown always preserves its content as plain text, meaning you can't do something like:
 
@@ -564,3 +565,39 @@ npm install @docusaurus/remark-plugin-npm2yarn
 ````
 
 Using the `{sync: true}` option would make all tab choices synced. Because the choice is stored under the same namespace `npm2yarn`, different `npm2yarn` plugin instances would also sync their choices.
+
+## Usage in JSX {#usage-in-jsx}
+
+Outside of Markdown, you can use the `@theme/CodeBlock` component to get the same output.
+
+```jsx
+import CodeBlock from '@theme/CodeBlock';
+
+export default function MyReactPage() {
+  return (
+    <div>
+      {/* highlight-start */}
+      <CodeBlock language="jsx" title="/src/components/HelloCodeTitle.js">
+        {`function HelloCodeTitle(props) {
+  return <h1>Hello, {props.name}</h1>;
+}`}
+      </CodeBlock>
+      {/* highlight-end */}
+    </div>
+  );
+}
+```
+
+<BrowserWindow>
+  <CodeBlock language="jsx" title="/src/components/HelloCodeTitle.js">
+    {`function HelloCodeTitle(props) {
+  return <h1>Hello, {props.name}</h1>;
+}`}
+  </CodeBlock>
+</BrowserWindow>
+
+The props accepted are `language` and `title`, in the same way as you write Markdown code blocks.
+
+Although discouraged, you can also pass in a `metastring` prop like `metastring='{1-2} title="/src/components/HelloCodeTitle.js"'`, which is how Markdown code blocks are handled under the hood. However, we recommend you [use comments for highlighting lines](#highlighting-with-comments).
+
+As [previously stated](#using-jsx-markup), syntax highlighting is only applied when the children is a simple string.

website/docs/guides/markdown-features/markdown-features-react.mdx

@@ -116,17 +116,11 @@ import MyComponentSource from '!!raw-loader!@site/src/pages/examples/_myComponen
 <br />
 ```
 
-You can also pass `title` prop to `CodeBlock` component in order for it to appear as header above your code block:
+See [using code blocks in JSX](./markdown-features-code-blocks.mdx#usage-in-jsx) for more details of the `<CodeBlock>` component.
-
-```jsx
-<CodeBlock className="language-jsx" title="/src/myComponent">
-  {MyComponentSource}
-</CodeBlock>
-```
 
 :::note
 
-You have to use `<CodeBlock>` rather than the Markdown triple-backtick ` ``` `, because the latter will ship out any of its content as-is, but you want JSX to insert the imported text here.
+You have to use `<CodeBlock>` rather than the Markdown triple-backtick ` ``` `, because the latter will ship out any of its content as-is, but you want to interpolate the imported text here.
 
 :::