Typing component props in Vue - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of typing component props in Vue?

Typing component props helps catch errors early by ensuring the data passed to components matches expected types. It improves code clarity and developer experience.

beginner

How do you define a prop with a specific type in Vue 3 using the Composition API?

You define props with types by using <code>defineProps&lt;Type&gt;()</code> inside the <code>&lt;script setup&gt;</code> block. For example: <code>const props = defineProps&lt;{ title: string }&gt;()</code>.

intermediate

What happens if a prop is passed with the wrong type in a typed Vue component?

If using TypeScript, the editor or build tool will show an error before running the app. At runtime, Vue may warn in the console if the prop type does not match the declared type.

intermediate

How can you make a prop optional with a default value in Vue 3 with TypeScript?

In <code>defineProps</code>, you can mark a prop as optional by adding <code>?</code> in the type and provide a default value using <code>withDefaults</code>. Example: <code>const props = withDefaults(defineProps&lt;{ count?: number }&gt;(), { count: 0 })</code>.

beginner

Why is typing props beneficial when working in larger Vue projects?

Typing props helps teams avoid bugs, improves code readability, and enables better tooling support like autocomplete and refactoring. It makes components easier to use and maintain.

Which Vue 3 feature allows you to type props directly in the <script setup> block?

A defineProps

B useProps

C propsType

D setProps

The defineProps function is used in Vue 3's <script setup> to declare and type component props.

How do you specify that a prop is optional with a default value in Vue 3 with TypeScript?

A Add <code>defaultValue</code> in the template

B Use <code>withDefaults</code> with <code>defineProps</code>

C Use <code>optionalProps</code> function

D Set <code>required: false</code> in the options object

Vue 3 uses withDefaults alongside defineProps to provide default values for optional props.

What type of error will you get if you pass a wrong type to a typed prop in Vue with TypeScript?

A No error, silently ignored

B Runtime crash

C Compile-time error

D Syntax error

TypeScript catches type mismatches at compile time, helping prevent runtime issues.

Which of these is NOT a benefit of typing props in Vue?

A Early error detection

B Improved code readability

C Better tooling support

D Automatic UI styling

Typing props does not affect UI styling; it helps with code quality and error checking.

In Vue 3, where do you typically write the prop type definitions when using the Composition API?

A Inside the <code>&lt;script setup&gt;</code> block

B In the template section

C In a separate CSS file

D In the main.js file

Prop types are declared inside the <script setup> block using defineProps.

Explain how to type component props in Vue 3 using the Composition API and how to provide default values.

Think about how you declare props inside <code>&lt;script setup&gt;</code> and how defaults are added.

Describe the benefits of typing props in Vue components for a team project.

Consider how typing helps both developers and the project quality.