vue 3 emit warning ” Extraneous non-emits event listeners”

I think you need to define the emits in your component: https://v3.vuejs.org/guide/component-custom-events.html#defining-custom-events

export default {
  name: "HelloWorld",
  emits: ["updatedcount"], // <--- add this line
  setup(_,{ emit }) {
    ...
  },
};