WIP

Author: AugustinMauroy

recipes/cjs-to-esm/codemod.yml

@@ -20,3 +20,6 @@ keywords:
 registry:
   access: public
   visibility: public
+
+capabilities:
+  - fs

recipes/cjs-to-esm/src/extension-change.ts

@@ -0,0 +1,46 @@
+import fs from 'node:fs';
+import path from 'node:path';
+import {
+	getOrSetStepOutput,
+	setStepOutput,
+} from '@codemod.com/jssg-types/workflow';
+import type { SgRoot } from '@codemod.com/jssg-types/main';
+import type JS from '@codemod.com/jssg-types/langs/javascript';
+
+const STEP_ID = 'change-extensions';
+const OUTPUT_NAME = 'extension_changes';
+
+export default async function transform(
+	root: SgRoot<JS>,
+): Promise<string | null> {
+	const sourcePath = root.filename();
+	if (!sourcePath || sourcePath === 'anonymous') return null;
+
+	if (!sourcePath.endsWith('.cjs') && !sourcePath.endsWith('.mjs')) return null;
+
+	const targetPath = sourcePath.replace(/\.(c|m)js$/i, '.js');
+	if (targetPath === sourcePath) return null;
+
+	fs.renameSync(sourcePath, targetPath);
+
+	const from = path.normalize(path.resolve(sourcePath));
+	const to = path.normalize(path.resolve(targetPath));
+
+	const existingRaw = getOrSetStepOutput(STEP_ID, OUTPUT_NAME, '[]');
+	let mappings: Array<{ from: string; to: string }> = [];
+
+	try {
+		const parsed = JSON.parse(existingRaw);
+		if (Array.isArray(parsed)) mappings = parsed;
+	} catch (error) {
+		console.warn(
+			'Failed to parse existing extension changes; resetting list',
+			error,
+		);
+	}
+
+	mappings.push({ from, to });
+	setStepOutput(OUTPUT_NAME, JSON.stringify(mappings));
+
+	return null;
+}

recipes/cjs-to-esm/workflow.yaml

@@ -1,8 +1,41 @@
 version: "1"
 
+state:
+  schema:
+    extension_changes:
+      description: Tracks files renamed from .cjs/.mjs to .js for downstream specifier fixes
+      type: array
+      items:
+        type: object
+        properties:
+          from:
+            type: string
+          to:
+            type: string
+
 nodes:
+  - id: normalize-extensions
+    name: Normalize file extensions
+    type: automatic
+    runtime:
+      type: direct
+    steps:
+      - id: change-extensions
+        name: Rename .cjs/.mjs files to .js and record mapping
+        js-ast-grep:
+          js_file: src/extension-change.ts
+          base_path: .
+          include:
+            - "**/*.cjs"
+            - "**/*.mjs"
+          exclude:
+            - "**/node_modules/**"
+          language: typescript
+
   - id: apply-transforms
     name: Apply AST transformations
+    depends_on:
+      - normalize-extensions
     type: automatic
     runtime:
       type: direct