CLI: Automigrate from MDX1 to MDX2

code/lib/cli/src/automigrate/fixes/index.ts

@@ -1,3 +1,5 @@
+import { Fix } from '../types';
+
 import { cra5 } from './cra5';
 import { webpack5 } from './webpack5';
 import { angular12 } from './angular12';
@@ -9,7 +11,7 @@ import { npm7 } from './npm7';
 import { sbScripts } from './sb-scripts';
 import { newFrameworks } from './new-frameworks';
 import { removedGlobalClientAPIs } from './remove-global-client-apis';
-import { Fix } from '../types';
+import { mdx1to2 } from './mdx-1-to-2';
 
 export * from '../types';
 
@@ -25,4 +27,5 @@ export const fixes: Fix[] = [
   sbScripts,
   newFrameworks,
   removedGlobalClientAPIs,
+  mdx1to2,
 ];

code/lib/cli/src/automigrate/fixes/mdx-1-to-2.test.ts

@@ -0,0 +1,50 @@
+/// <reference types="@types/jest" />;
+
+import { dedent } from 'ts-dedent';
+import { fixMdxScript } from './mdx-1-to-2';
+
+describe('fix', () => {
+  it('fixes badly-formatted style blocks', () => {
+    expect(
+      fixMdxScript(dedent`
+        <style>{\`
+          .foo {}
+
+          .bar {}
+        \`}</style>
+      `)
+    ).toEqual(dedent`
+      <style>
+        {\`
+        .foo {}
+
+        .bar {}
+        \`}
+      </style>
+    `);
+  });
+
+  it('fixes multiple style blocks', () => {
+    expect(
+      fixMdxScript(dedent`
+        <style>{\`
+          .foo {}
+        \`}</style>
+        <style>{\`
+          .bar {}
+        \`}</style>
+      `)
+    ).toMatchInlineSnapshot(`
+      <style>
+        {\`
+        .foo {}
+        \`}
+      </style>
+      <style>
+        {\`
+        .bar {}
+        \`}
+      </style>
+    `);
+  });
+});

code/lib/cli/src/automigrate/fixes/mdx-1-to-2.ts

@@ -0,0 +1,66 @@
+import chalk from 'chalk';
+import { dedent } from 'ts-dedent';
+import { basename } from 'path';
+import fse from 'fs-extra';
+import globby from 'globby';
+import type { Fix } from '../types';
+
+const MDX1_SCRIPT_START = /<style>{`/g;
+const MDX1_SCRIPT_END = /`}<\/style>/g;
+
+export const fixMdxScript = (mdx: string) => {
+  return mdx.replace(MDX1_SCRIPT_START, '<style>\n  {`').replace(MDX1_SCRIPT_END, '  `}\n</style>');
+};
+
+const logger = console;
+
+interface Mdx1to2Options {
+  storiesMdxFiles: string[];
+}
+
+/**
+ * Does the user have `.stories.mdx` files?
+ *
+ * If so:
+ * - Assume they might be MDX1
+ * - Offer to help migrate to MDX2
+ */
+export const mdx1to2: Fix<Mdx1to2Options> = {
+  id: 'mdx1to2',
+
+  async check() {
+    const storiesMdxFiles = await globby('**/*.(story|stories).mdx');
+    return storiesMdxFiles.length ? { storiesMdxFiles } : undefined;
+  },
+
+  prompt({ storiesMdxFiles }) {
+    return dedent`
+      We've found ${chalk.yellow(storiesMdxFiles.length)} '.stories.mdx' files in your project.
+
+      Storybook has upgraded to MDX2 (https://mdxjs.com/blog/v2/), which contains breaking changes from V1.
+
+      We can try to automatically upgrade your MDX files to MDX2 format using some common patterns.
+
+      For a full guide for how to manually upgrade your files, see the MDX2 migration guide:
+
+      ${chalk.cyan('https://mdxjs.com/migrating/v2/#update-mdx-files')}
+    `;
+  },
+
+  async run({ result: { storiesMdxFiles }, dryRun }) {
+    await Promise.all(
+      storiesMdxFiles.map(async (fname) => {
+        const contents = await fse.readFile(fname, 'utf-8');
+        const updated = fixMdxScript(contents);
+        if (updated === contents) {
+          logger.info(`🆗 Unmodified ${basename(fname)}`);
+        } else {
+          logger.info(`✅ Modified ${basename(fname)}`);
+          if (!dryRun) {
+            await fse.writeFile(fname, updated);
+          }
+        }
+      })
+    );
+  },
+};