import babel from 'rollup-plugin-babel';
import uglify from 'rollup-plugin-uglify';

export default {
  entry: 'lindenmayer.js',
  format: 'cjs',
  plugins: [ babel() /*uglify()*/ ],
  targets: [
    { dest: 'dist/lindenmayer.js', format: 'cjs' },
    { dest: 'dist/lindenmayer.browser.js', format: 'iife' },
    { dest: 'dist/lindenmayer.es.js', format: 'es' },
  ],
  moduleName: 'LSystem'
};

import babel from 'rollup-plugin-babel';
import uglify from 'rollup-plugin-uglify';

export default {
  entry: 'lindenmayer.js',
  format: 'cjs',
  plugins: [ babel(), /*uglify()*/ ],
  dest: 'dist/lindenmayer.js',
  moduleName: 'LSystem'
};

--- 
+++ 
@@ -4,7 +4,11 @@
 export default {
   entry: 'lindenmayer.js',
   format: 'cjs',
-  plugins: [ babel(), /*uglify()*/ ],
-  dest: 'dist/lindenmayer.js',
+  plugins: [ babel() /*uglify()*/ ],
+  targets: [
+    { dest: 'dist/lindenmayer.js', format: 'cjs' },
+    { dest: 'dist/lindenmayer.browser.js', format: 'iife' },
+    { dest: 'dist/lindenmayer.es.js', format: 'es' },
+  ],
   moduleName: 'LSystem'
 };
Make use of module field for ES module support. Babel for some previous browser versions.
