Add CommonJS build for compatibility with ESLint < 9

Author: TrevorBurnham

package.json

@@ -15,14 +15,15 @@
   "exports": {
     ".": {
       "types": "./dist/index.d.ts",
-      "import": "./dist/index.js"
+      "import": "./dist/index.js",
+      "require": "./dist/index.cjs"
     }
   },
   "files": [
     "dist"
   ],
   "scripts": {
-    "build": "tsc",
+    "build": "node scripts/build.js",
     "format": "eslint . --fix && prettier . --log-level warn --write",
     "test": "vitest",
     "release": "np"
@@ -48,6 +49,6 @@
     "vitest": "^1.3.1"
   },
   "peerDependencies": {
-    "eslint": "^8.0.0"
+    "eslint": ">=8.0.0"
   }
 }

scripts/build.js

@@ -0,0 +1,38 @@
+import { readdir, rename, rm } from 'node:fs/promises';
+import { join, dirname } from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const cjsDir = join(__dirname, '../dist/cjs-temp');
+const distDir = join(__dirname, '../dist');
+
+async function renameCjsFiles() {
+  // Recursively get all .js files
+  async function getJsFiles(dir) {
+    const entries = await readdir(dir, { withFileTypes: true });
+    const files = await Promise.all(entries.map((entry) => {
+      const res = join(dir, entry.name);
+      return entry.isDirectory() ? getJsFiles(res) : res;
+    }));
+    return files.flat().filter(file => file.endsWith('.js'));
+  }
+
+  // Rename all .js files to .cjs and move them to dist
+  const jsFiles = await getJsFiles(cjsDir);
+  await Promise.all(jsFiles.map(async (file) => {
+    const relativePath = file.split('cjs-temp/')[1];
+    const destPath = join(distDir, relativePath.replace('.js', '.cjs'));
+    await rename(file, destPath);
+  }));
+
+  // Clean up temporary directory
+  await rm(cjsDir, { recursive: true });
+}
+
+// Run TypeScript builds
+const { execSync } = await import('node:child_process');
+execSync('tsc -p tsconfig.json', { stdio: 'inherit' });
+execSync('tsc -p tsconfig.cjs.json', { stdio: 'inherit' });
+
+// Rename CJS files
+await renameCjsFiles();

tsconfig.cjs.json

@@ -0,0 +1,8 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "module": "CommonJS",
+    "moduleResolution": "Node",
+    "outDir": "./dist/cjs-temp"
+  }
+}