add missing "type": "commonjs" to DEV-cjs output (#2194)

.changeset/early-teachers-bathe.md

@@ -0,0 +1,5 @@
+---
+'@itwin/itwinui-react': patch
+---
+
+The development build output is now also formatted using `prettier` for easier debugging.

.changeset/yellow-glasses-cover.md

@@ -0,0 +1,5 @@
+---
+'@itwin/itwinui-react': patch
+---
+
+Fixed an issue where CommonJS files in the development build output (`DEV-cjs/` directory) were being treated as ESM, inadvertently causing runtime errors during development.

packages/itwinui-react/scripts/postBuild.mjs

@@ -5,19 +5,20 @@
 import fs from 'node:fs';
 import { execSync } from 'node:child_process';
 
-// This creates a dummy package.json file in the cjs folder.
+// This creates a dummy package.json file in the cjs and DEV-cjs folders.
 // Without this, all cjs files would need the .cjs extension
 // because .js files are treated as ESM according to the main package.json's "type".
 try {
   fs.writeFileSync('cjs/package.json', '{ "type": "commonjs" }');
+  fs.writeFileSync('DEV-cjs/package.json', '{ "type": "commonjs" }');
 } catch (e) {
-  console.error('Cannot create cjs/package.json', e);
+  console.error('Cannot create package.json', e);
 }
 
-// Run prettier on all compiled output because it gets jumbled by tsc.
+// Run prettier on all compiled output because it gets jumbled by SWC.
 try {
   execSync(
-    'npx prettier --write --ignore-path="../../.gitignore" "{esm,cjs}/**/*.js"',
+    'npx prettier --write --ignore-path="../../.gitignore" "{esm,cjs,DEV-esm,DEV-cjs}/**/*.js"',
   );
 } catch (error) {
   console.error('Error when running prettier', error);