Setup function basics in Vue - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the setup() function in Vue 3?

The setup() function is where you write the logic for a Vue component using the Composition API. It runs before the component is created and returns the data and methods that the template can use.

beginner

How do you return reactive data from the setup() function?

You return an object containing reactive references (like ref or reactive) or plain values. These become available in the component's template.

beginner

Which Vue 3 API is commonly used inside setup() to create a reactive variable?

The ref() function is used to create a reactive variable that can hold a single value and update the template when changed.

intermediate

Can you access component properties like props and context inside setup()?

Yes, setup() receives props and context as arguments, allowing you to use props and emit events or access slots.

intermediate

Why is setup() considered better for organizing code than the Options API?

Because setup() groups related logic together, making code easier to read and maintain, especially in larger components.

What does the setup() function return in a Vue component?

A Nothing, it only runs code

B A string with HTML content

C A Vue instance

D An object with data and methods for the template

The setup() function returns an object whose properties are exposed to the template for rendering and interaction.

Which of these is a reactive reference you can create inside setup()?

A ref()

B reactiveVar()

C watch()

D computed()

ref() creates a reactive reference holding a value that updates the template when changed.

How do you access component props inside setup()?

A Using <code>props()</code> function

B Using <code>this.props</code>

C They are passed as the first argument to <code>setup()</code>

D Props are not accessible in <code>setup()</code>

Props are passed as the first argument to setup(props, context).

Which Vue 3 feature does setup() belong to?

A Composition API

B Options API

C Vue Router

D Vuex

setup() is the entry point for the Composition API in Vue 3.

What is the benefit of using setup() over Options API?

A It runs faster in the browser

B Better code organization by grouping related logic

C It automatically styles components

D It replaces the need for templates

setup() helps organize code by logic rather than by option type, improving readability.

Explain how the setup() function works in a Vue 3 component and what it returns.

Think about how you prepare data and methods for the template.

Describe how to create and use a reactive variable inside the setup() function.

Remember how Vue tracks changes to update the UI.