feat(runtime-dom): defineCustomElement

packages/runtime-core/src/component.ts

@@ -279,12 +279,15 @@ export interface ComponentInternalInstance {
    * @internal
    */
   emitsOptions: ObjectEmitsOptions | null
-
   /**
    * resolved inheritAttrs options
    * @internal
    */
   inheritAttrs?: boolean
+  /**
+   * is custom element?
+   */
+  isCE?: boolean
 
   // the rest are only for stateful components ---------------------------------
 
@@ -519,6 +522,11 @@ export function createComponentInstance(
   instance.root = parent ? parent.root : instance
   instance.emit = emit.bind(null, instance)
 
+  // apply custom element special handling
+  if (vnode.ce) {
+    vnode.ce(instance)
+  }
+
   return instance
 }