Beginner LevelVue JS
How do you validate component props with types, required flags, and defaults in Vue?
❓ Interview Prompt: Explain prop validation in Vue 3: defineProps<T> TypeScript interfaces vs runtime object declarations.
Props pass data down from parent components to child components. Vue provides prop validation to enforce data contracts:
1. TypeScript Type-Based Props ('defineProps<T>()'):
Pass a TypeScript interface directly to 'defineProps<T>()'. Use 'withDefaults()' compiler macro to specify default prop values.
2. Runtime Object Props ('defineProps({...})'):
Declare prop types, required flags, and default factory functions at runtime:
'defineProps({ count: { type: Number, default: 0, required: true } })'.
Code Implementation Example
html
<script setup lang="ts">
// TypeScript Prop Declaration with Defaults (Vue 3 standard)
interface Props {
title: string;
count?: number;
tags?: string[];
}
const props = withDefaults(defineProps<Props>(), {
count: 0,
tags: () => ['general'] // Default factory function for arrays/objects
});
</script>
<template>
<h3>{{ title }} (Count: {{ count }})</h3>
</template>💡Validating Vue 3 component props using TypeScript defineProps and withDefaults.
🎯 Interview Key Takeaway
Use defineProps<T>() with withDefaults() in TypeScript for type-safe component prop validation.
#defineProps#Props#TypeScript#Beginner
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