vue3 props emit

Vue 3 introduces a few changes in the way props and emit are handled compared to Vue 2. Here's how you can use props and emit in Vue 3:

1. Props:
- In Vue 3, props are declared using the `props` option inside the component setup. You can define the props as an object with the desired prop names as keys and their respective types as values.
- For example, to define a prop named "message" of type String, you can do:

     import { defineComponent } from 'vue';

     export default defineComponent({
       props: {
         message: {
           type: String,
           required: true, // optional, if the prop is required
           default: 'Hello!', // optional, default value for the prop
         },
       },
     });

2. Emitting Events:
- In Vue 3, emitting events is done through the `emit` function that is available inside the component's setup.
- To emit an event, you call `emit` with the event name and any additional payload data.
- For example, to emit an event named "update" with a payload of "newValue", you can do:

     import { defineComponent } from 'vue';

     export default defineComponent({
       methods: {
         updateValue(newValue) {
           this.$emit('update', newValue);
         },
       },
     });

Remember to import the necessary functions (`defineComponent`, etc.) from the 'vue' package. I hope this helps!