Get your own Vue server
App.vue
ChildComp.vue
main.js
 
<template>
  <div>
    <h3>ChildComp.vue</h3>
    <p>Click the button to trigger the custom event with the "Hello!" message up to the parent component using the $emit() method.</p>
    <button v-on:click="notifyParent">Trigger</button>
  </div>
</template>

<script>
export default {
  emits: ['custom-event'],
  methods: {
    notifyParent() {
      this.$emit('custom-event','Hello! ')
    }
  }
}
</script>

<style scoped>
div {
  border: solid black 1px;
  padding: 10px;
  max-width: 350px;
  margin-top: 20px;
}
</style>                  
http://localhost:5173/