feat: compatibility with modern web bundlers and browsers (diegomura#1891)

Co-authored-by: diegomura <diegomuracciole@gmail.com>

Author: carlobeltrame

package.json

@@ -5,16 +5,17 @@
   "description": "React-pdf helper functions",
   "author": "Diego Muracciole <diegomuracciole@gmail.com>",
   "homepage": "https://github.com/diegomura/react-pdf#readme",
-  "main": "lib/index.js",
+  "main": "lib/index.cjs.js",
+  "module": "lib/index.es.js",
   "repository": {
     "type": "git",
     "url": "https://github.com/diegomura/react-pdf.git",
     "directory": "packages/fns"
   },
   "scripts": {
     "test": "jest",
-    "build": "rimraf ./lib && babel src --out-dir lib",
-    "watch": "rimraf ./lib && babel src --out-dir lib --watch"
+    "build": "rimraf ./lib && rollup -c",
+    "watch": "rimraf ./lib && rollup -c -w"
   },
   "files": [
     "lib"

rollup.config.js

@@ -0,0 +1,38 @@
+import babel from '@rollup/plugin-babel';
+import pkg from './package.json';
+
+const cjs = {
+  exports: 'named',
+  format: 'cjs',
+};
+
+const esm = {
+  format: 'es',
+};
+
+const getCJS = override => Object.assign({}, cjs, override);
+const getESM = override => Object.assign({}, esm, override);
+
+const input = 'src/index.js';
+
+const getExternal = () => [/@babel\/runtime/];
+
+const getPlugins = () => [
+  babel({
+    babelrc: true,
+    babelHelpers: 'runtime',
+    exclude: 'node_modules/**',
+  }),
+];
+
+const config = {
+  input,
+  output: [
+    getESM({ file: 'lib/index.es.js' }),
+    getCJS({ file: 'lib/index.cjs.js' }),
+  ],
+  external: getExternal(),
+  plugins: getPlugins(),
+};
+
+export default config;