refactor: switch to native ESM with exports

Removes unneeded devDeps. and `module` property; switches to cjs extension for CommonJS build

Author: brettz9

.gitignore

@@ -1,3 +1,3 @@
 /node_modules
 /package-lock.json
-index.cjs.js
+index.cjs

constructor/build.js

@@ -1,7 +1,7 @@
 import path from "path";
 import { rollup } from "rollup";
 
-const PATH_ROOT = path.resolve(__dirname, "../");
+const PATH_ROOT = path.resolve(import.meta.dirname, "../");
 
 let inputOptions = {
     input: path.resolve(PATH_ROOT, "index.js"),
@@ -10,10 +10,10 @@ let inputOptions = {
 
 let outputOptions = {
     output: {
-        file: path.resolve(PATH_ROOT, "index.cjs.js"),
+        file: path.resolve(PATH_ROOT, "index.cjs"),
         format: "cjs",
-        banner: "// DO NOT edit this file, it's auto generate from 'constructor/build.js', any changes will be overwrite. \n"
+        banner: "// DO NOT edit this file, it's auto-generated from 'constructor/build.js'; any changes will be overwritten. \n"
     }
 }
 
-rollup(inputOptions).then(bundle => bundle.write(outputOptions));
+rollup(inputOptions).then(bundle => bundle.write(outputOptions));

package.json

@@ -3,8 +3,12 @@
   "description": "Modern, fast React.js JSX parser",
   "homepage": "https://github.com/acornjs/acorn-jsx",
   "version": "5.3.2",
+  "type": "module",
   "main": "index.cjs.js",
-  "module": "index.js",
+  "exports": {
+    "import": "./index.js",
+    "require": "./index.cjs"
+  },
   "maintainers": [
     {
       "name": "Ingvar Stepanyan",
@@ -18,16 +22,14 @@
   },
   "license": "MIT",
   "scripts": {
-    "test": "node -r esm test/run.js",
-    "prepublishOnly": "node -r esm constructor/build.js"
+    "test": "node test/run.js",
+    "prepublishOnly": "node constructor/build.js"
   },
   "peerDependencies": {
     "acorn": "^6.0.0 || ^7.0.0 || ^8.0.0"
   },
   "devDependencies": {
-    "@rollup/plugin-commonjs": "^12.0.0",
     "acorn": "^8.0.1",
-    "esm": "^3.2.25",
     "rollup": "^2.12.0"
   }
 }