Support ES Module output in npm package. #862

package.json

@@ -12,10 +12,12 @@
   "repository": "markdown-it/markdown-it",
   "license": "MIT",
   "main": "index.js",
+  "module": "dist/esm/markdown-it.mjs",
   "bin": {
     "markdown-it": "bin/markdown-it.js"
   },
   "scripts": {
+    "build": "rollup -c support/rollup.config.js",
     "lint": "eslint .",
     "test": "npm run lint && nyc mocha && node support/specsplit.js",
     "coverage": "npm run test && nyc report --reporter html",

support/rollup.config.js

@@ -5,14 +5,7 @@ import nodePolyfills from 'rollup-plugin-node-polyfills';
 import pkg from '../package.json';
 import { terser } from 'rollup-plugin-terser';
 
-export default {
-  input: 'index.js',
-  output: [
-    {
-      file: 'dist/markdown-it.js',
-      format: 'umd',
-      name: 'markdownit',
-      plugins: [
+const unminifiedPlugins = [
   // Here terser is used only to force ascii output
   terser({
     mangle: false,
@@ -24,19 +17,42 @@ export default {
       indent_level: 2
     }
   })
-      ]
-    },
-    {
-      file: 'dist/markdown-it.min.js',
-      format: 'umd',
-      name: 'markdownit',
-      plugins: [
+];
+
+const minifiedPlugins = [
   terser({
     format: {
       ascii_only: true,
     }
   })
-      ]
+];
+
+export default {
+  input: 'index.js',
+  output: [
+    {
+      file: 'dist/markdown-it.js',
+      format: 'umd',
+      name: 'markdownit',
+      plugins: unminifiedPlugins,
+    },
+    {
+      file: 'dist/markdown-it.min.js',
+      format: 'umd',
+      name: 'markdownit',
+      plugins: minifiedPlugins,
+    },
+    {
+      file: 'dist/esm/markdown-it.mjs',
+      format: 'es',
+      name: 'markdownit',
+      plugins: unminifiedPlugins,
+    },
+    {
+      file: 'dist/esm/markdown-it.min.mjs',
+      format: 'es',
+      name: 'markdownit',
+      plugins: minifiedPlugins,
     }
   ],
   plugins: [