feat: refactor to use modern exports

this should follow the suggested format from Microbundle

Author: thebuilder

package.json

@@ -2,11 +2,15 @@
   "name": "react-intersection-observer",
   "version": "8.26.1",
   "description": "Monitor if a component is inside the viewport, using IntersectionObserver API",
-  "source": "src/index.tsx",
-  "main": "dist/react-intersection-observer.js",
-  "module": "dist/react-intersection-observer.m.js",
-  "unpkg": "dist/react-intersection-observer.umd.js",
-  "typings": "dist/index.d.ts",
+  "source": "./src/index.tsx",
+  "main": "./dist/react-intersection-observer.js",
+  "module": "./dist/react-intersection-observer.mjs",
+  "exports": {
+    "require": "./dist/react-intersection-observer.js",
+    "default": "./dist/react-intersection-observer.modern.mjs"
+  },
+  "unpkg": "./dist/react-intersection-observer.umd.js",
+  "typings": "./dist/index.d.ts",
   "author": "Daniel Schmidt",
   "sideEffects": false,
   "repository": {
@@ -89,19 +93,19 @@
   },
   "size-limit": [
     {
-      "path": "dist/react-intersection-observer.m.js",
+      "path": "dist/react-intersection-observer.mjs",
       "name": "InView",
       "import": "{ InView }",
       "limit": "1.8 kB"
     },
     {
-      "path": "dist/react-intersection-observer.m.js",
+      "path": "dist/react-intersection-observer.mjs",
       "name": "useInView",
       "import": "{ useInView }",
       "limit": "1.3 kB"
     },
     {
-      "path": "dist/react-intersection-observer.m.js",
+      "path": "dist/react-intersection-observer.mjs",
       "name": "observe",
       "import": "{ observe }",
       "limit": "1 kB"

scripts/build-copy.js

@@ -29,8 +29,25 @@ packageFieldsToRemove.forEach((field) => {
 });
 
 // Remove 'dist' from the files inside the 'dist' dir, after we move them
-const fields = ['main', 'module', 'unpkg', 'esmodule', 'exports', 'typings'];
-fields.forEach((key) => (pck[key] = pck[key]?.replace('dist/', '')));
+const fields = [
+  'main',
+  'module',
+  'unpkg',
+  'exports',
+  'esmodule',
+  'exports',
+  'typings',
+];
+fields.forEach((key) => {
+  if (typeof pck[key] === 'object') {
+    const keys = Object.keys(pck[key]);
+    keys.forEach((subkey) => {
+      pck[key][subkey] = pck[key][subkey]?.replace('./dist/', './');
+    });
+  } else {
+    pck[key] = pck[key]?.replace('./dist/', './');
+  }
+});
 
 fs.writeFileSync(
   path.resolve(distDir, 'package.json'),