Added babel

.babelrc

@@ -0,0 +1,25 @@
+{
+  "presets": [
+    [
+      "@babel/preset-env",
+      {
+        "modules": false,
+        "targets": {
+          "esmodules": true
+        }
+      }
+    ],
+    ["minify"]
+  ],
+  "plugins": [
+    [
+      "@babel/plugin-proposal-decorators",
+      { "legacy": true }
+    ],
+    [
+      "@babel/plugin-proposal-class-properties",
+      { "loose": true }
+    ],
+    ["@babel/plugin-transform-template-literals"]
+  ]
+}

mini-media-player.js

@@ -63,7 +63,7 @@ class MiniMediaPlayer extends LitElement {
     if (!config.entity || config.entity.split('.')[0] !== 'media_player')
       throw new Error('Specify an entity from within the media_player domain.');
 
-    const conf = Object.assign({
+    const conf = {
       artwork: 'default',
       artwork_border: false,
       background: false,
@@ -90,8 +90,9 @@ class MiniMediaPlayer extends LitElement {
       show_tts: false,
       title: '',
       toggle_power: true,
-      volume_stateless: false
-    }, config);
+      volume_stateless: false,
+      ...config
+    };
     conf.consider_idle_after = Number(conf.consider_idle_after) * 60 || false;
     conf.idle_view = conf.idle_view
       || conf.consider_idle_after
@@ -223,10 +224,11 @@ class MiniMediaPlayer extends LitElement {
   _renderMediaInfo() {
     if (this.config.hide_media_info) return;
     const items = MEDIA_INFO.map(item => {
-      return Object.assign({
+      return {
         info: this._getAttribute(item.attr),
-        prefix: item.prefix || ''
-      }, item);
+        prefix: item.prefix || '',
+        ...item
+      };
     }).filter(item => item.info !== '');
 
     return html`

package.json

@@ -1,12 +1,20 @@
 {
   "devDependencies": {
+    "@babel/cli": "^7.1.5",
+    "@babel/core": "^7.1.5",
+    "@babel/plugin-proposal-class-properties": "^7.1.0",
+    "@babel/plugin-proposal-decorators": "^7.1.2",
+    "@babel/plugin-transform-template-literals": "^7.0.0",
+    "@babel/preset-env": "^7.1.5",
     "@polymer/lit-element": "^0.6.2",
+    "babel-preset-minify": "^0.5.0",
     "rollup": "^0.66.6",
     "rollup-plugin-node-resolve": "^3.4.0",
     "rollup-plugin-replace": "^2.1.0",
     "rollup-plugin-terser": "^3.0.0"
   },
   "scripts": {
-    "build": "rollup -c"
+    "build": "rollup -c && babel mini-media-player-bundle.js --out-file mini-media-player-bundle.js",
+    "rollup": "rollup -c"
   }
 }

rollup.config.js

@@ -6,7 +6,7 @@ export default {
   input: 'mini-media-player.js',
   output: {
     file: 'mini-media-player-bundle.js',
-    format: 'esm'
+    format: 'umd'
   },
   plugins: [
     replace({