Add Rollup config

package.json

@@ -2,10 +2,9 @@
   "name": "html2pdf",
   "version": "0.7.6",
   "description": "Client-side HTML-to-PDF rendering using pure JS",
-  "main": "dist/html2pdf.js",
-  "scripts": {
-    "test": "echo \"Error: no test specified\" && exit 1"
-  },
+  "main": "dist/require/html2pdf.cjs.js",
+  "module": "dist/include/html2pdf.es.js",
+  "browser": "dist/html2pdf.js",
   "repository": {
     "type": "git",
     "url": "git+https://github.com/eKoopmans/html2pdf.git"
@@ -29,6 +28,13 @@
   "homepage": "https://github.com/eKoopmans/html2pdf",
   "dependencies": {
     "html2canvas": "https://github.com/eKoopmans/html2canvas/tarball/develop",
-    "jspdf": "1.3.5"
+    "jspdf": "^1.3.5"
+  },
+  "devDependencies": {
+    "rollup": "^0.51.8"
+  },
+  "scripts": {
+    "build": "npm install && rollup -c",
+    "test": "echo \"Error: no test specified\" && exit 1"
   }
 }

rollup.config.js

@@ -0,0 +1,27 @@
+// Import dependencies.
+import resolve from 'rollup-plugin-node-resolve';
+import commonjs from 'rollup-plugin-commonjs';
+import pkg from './package.json';
+
+export default [
+  // Bundled builds.
+  {
+    input: 'src/index.js',
+    output: [
+      { file: pkg.main.replace(/js$/, 'bundle.js'), format: 'cjs' },
+      { file: pkg.module.replace(/js$/, 'bundle.js'), format: 'es' },
+      { file: pkg.browser.replace(/js$/, 'bundle.js'), format: 'iife' },
+      { file: pkg.browser.replace(/js$/, 'umd.bundle.js'), format: 'umd' }
+    ]
+  },
+  // Un-bundled builds.
+  {
+    input: 'src/index.js',
+    output: [
+      { file: pkg.main, format: 'cjs' },
+      { file: pkg.module, format: 'es' },
+      { file: pkg.browser, format: 'iife' },
+      { file: pkg.browser.replace(/js$/, 'umd.js'), format: 'umd' }
+    ]
+  }
+];