move shadow innerHTML to constructor

Author: halvves

src/shader-doodle.js

@@ -14,12 +14,11 @@ class ShaderDoodleElement extends SDNodeElement {
   constructor() {
     super();
     this.shadow = this.attachShadow({ mode: 'open' });
-  }
-
-  connectedCallback() {
     this.shadow.innerHTML = Template.render(this.width, this.height);
     this.canvas = Template.map(this.shadow).canvas;
+  }
 
+  connectedCallback() {
     setTimeout(() => {
       try {
         this.init();