Sharing composables across components in Vue - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a composable in Vue 3?

A composable is a reusable function that uses Vue's Composition API to share reactive state and logic across components.

beginner

How do you share a composable between multiple Vue components?

You create a composable function in a separate file and import it into any component that needs the shared logic or state.

intermediate

Why should composables be pure functions without side effects?

Pure composables are easier to reuse and test because they don't depend on or change external state unexpectedly.

intermediate

What Vue 3 feature allows composables to share reactive state across components?

Vue 3's reactive and ref functions allow composables to create reactive state that components can use and update.

advanced

How can you avoid creating multiple independent states when using a composable in different components?

You can create a shared reactive state outside the composable function or use a singleton pattern so all components use the same state instance.

What is the main purpose of a composable in Vue 3?

A To share reusable logic and state across components

B To style components with CSS

C To define routes in the app

D To create templates for components

Composable functions let you share logic and reactive state easily between components.

How do you use a composable in a Vue component?

A Add it as a component property

B Import the composable function and call it inside the setup() function

C Use it only in the main.js file

D Write the composable code inside the template

You import the composable and call it inside setup() to access its reactive state and functions.

If you want all components to share the same reactive state from a composable, what should you do?

A Use a different composable for each component

B Define the reactive state inside each component separately

C Use Vuex instead of composables

D Define the reactive state outside the composable function

Defining reactive state outside the composable function creates a shared singleton state.

Which Vue 3 API is commonly used inside composables to create reactive variables?

A watch()

B computed()

C ref()

D provide()

ref() creates reactive variables that composables can return and components can use.

What is a benefit of using composables over mixins in Vue 3?

A Composables avoid naming conflicts and are easier to read

B Mixins are faster to load

C Composables require less code than mixins

D Mixins support reactive state better

Composables provide clearer, more flexible code without the naming conflicts common in mixins.

Explain how you would create and share a composable that tracks a counter value across multiple Vue components.

Think about how reactive state and functions can be reused by importing.

Describe the difference between having reactive state inside a composable function versus outside it when sharing across components.

Consider how JavaScript closures and imports affect state instances.