vue3defineprops

Vue 3 defineProps is a new feature that allows the definition of props for a component in a more type-safe and efficient manner. In Vue 2, props are defined using the props option, which is an object that contains the names and types of all the props a component can receive. This approach has some limitations, such as the inability to validate or enforce prop types at runtime.

In Vue 3, defineProps is used to define props inside of the setup function. It returns an object that contains all the props specified, with their values being passed in from the parent component. The main advantage of using defineProps is that the props are now reactive, which means that if their values change, the component will re-render.

Here's an example of how to use defineProps in a Vue 3 component:

<template>
  <div>
    {{ message }}
  </div>
</template>

<script>
import { defineProps } from 'vue';

export default {
  setup(props) {
    const { message } = defineProps({
      message: {
        type: String,
        required: true
      }
    });

    return {
      message
    };
  }
}
</script>

In this example, we define a prop called message, which is of type String and is required. We then use defineProps to create a reactive message variable that holds the value of the message prop passed in from the parent component. The message variable is then used in the template to display the message.

Overall, defineProps is a powerful new feature in Vue 3 that makes it easier to define and work with props in a more type-safe and reactive manner.