[experiment] Drop CJS support, make it ESM-only

CHANGELOG.md

@@ -1,5 +1,15 @@
 ## [Unreleased]
 
+- Drops CJS support in favor of ESM only
+
+```tsx
+// ❌ No longer supported
+const { string } = require('decoders');
+
+// ✅ Use import instead
+import { string } from 'decoders';
+```
+
 ## [2.6.0] - 2025-02-04
 
 - Implement the [Standard Schema](https://standardschema.dev/) specification.

package.json

@@ -13,19 +13,12 @@
     "url": "https://github.com/nvie/decoders/issues"
   },
   "type": "module",
-  "main": "./dist/index.cjs",
-  "module": "./dist/index.js",
-  "types": "./dist/index.d.cts",
+  "main": "./dist/index.js",
   "exports": {
     ".": {
       "import": {
         "types": "./dist/index.d.ts",
         "default": "./dist/index.js"
-      },
-      "require": {
-        "types": "./dist/index.d.cts",
-        "module": "./dist/index.js",
-        "default": "./dist/index.cjs"
       }
     }
   },
@@ -40,7 +33,7 @@
     "docs": "cog -cr docs/*.md",
     "lint": "eslint --color --report-unused-disable-directives src/ test/ && prettier --list-different src/ test/ test-d/",
     "lint:docs": "cog -c --check docs/*.md || (npm run docs; git diff; echo 'Error: docs not up-to-date, please re-run \"npm docs\" to update them.' && exit 1)",
-    "lint:package": "publint --strict && attw --pack",
+    "lint:package": "publint --strict && attw --pack --profile esm-only",
     "format": "eslint --color --report-unused-disable-directives --fix src/ test/ ; prettier --write src/ test/ test-d/",
     "test": "vitest run --coverage",
     "test:completeness": "./bin/check.sh",

tsup.config.ts

@@ -6,5 +6,5 @@ export default defineConfig({
   splitting: true,
   clean: true,
   // target: /* what tsconfig specifies */,
-  format: ['esm', 'cjs'],
+  format: ['esm'],
 });