Props for parent to child data in Vue - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are props in Vue?

Props are custom attributes that allow a parent component to pass data down to a child component in Vue.

beginner

How do you declare props in a Vue 3 component using the Composition API?

You declare props by defining a <code>props</code> option in the <code>&lt;script setup&gt;</code> block, for example: <pre>const props = defineProps({ title: String })</pre>

intermediate

Why should props be treated as read-only inside child components?

Props are read-only to keep data flow predictable and avoid side effects. Changing props inside a child can cause bugs and breaks Vue's one-way data flow.

beginner

How can you pass a string and a number from a parent to a child component using props?

In the parent template, use:

<ChildComponent title="Hello" count="5" />

For numbers, use binding:

<ChildComponent :count="5" />

intermediate

What happens if a required prop is not passed to a child component in Vue?

Vue will warn in the console during development that a required prop is missing, helping catch errors early.

How do you pass data from a parent to a child component in Vue?

A Using slots

B Using events

C Using props

D Using watchers

Props are the way to send data from parent to child components in Vue.

In Vue 3 with <script setup>, how do you declare props?

A Using computed()

B Using defineProps()

C Using data()

D Using methods()

The defineProps() function declares props in the <script setup> block.

What is the correct way to pass a number prop named 'age' with value 30?

A <code>&lt;Child :age="30" /&gt;</code>

B <code>&lt;Child age="30" /&gt;</code>

C <code>&lt;Child :age="'30'" /&gt;</code>

D <code>&lt;Child age=30 /&gt;</code>

Using the colon (:) binds the number 30 as a number, not a string.

Can a child component modify the value of a prop it receives?

A Only if using v-model

B Yes, props can be changed freely

C Only if the prop is marked writable

D No, props are read-only inside the child

Props should be treated as read-only to maintain one-way data flow.

What will Vue do if a required prop is missing in development mode?

A Show a console warning

B Throw a runtime error

C Ignore silently

D Automatically assign a default value

Vue warns in the console to help developers catch missing required props.

Explain how props work in Vue to pass data from a parent to a child component.

Think about how a parent shares information with a child.

Describe how to declare and use props in a Vue 3 component using the <script setup> syntax.

Focus on the Composition API style.