Events for child to parent communication in Vue - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main purpose of using events for child to parent communication in Vue?

Events allow a child component to send messages or data to its parent component, enabling the parent to react or update based on the child's actions.

beginner

How does a child component emit an event to its parent in Vue 3?

The child uses the emit function provided by setup() or this.$emit in Options API to send a named event to the parent.

intermediate

In Vue 3 Composition API, how do you receive the emit function inside setup()?

You receive emit as the second argument in the setup(props, { emit }) function parameter.

beginner

What must the parent component do to listen to an event emitted by a child component?

The parent adds an event listener on the child component tag using @eventName="handlerMethod" syntax to respond when the child emits that event.

intermediate

Why is using events for child to parent communication preferred over directly modifying parent data from the child?

Events keep components loosely coupled and maintain Vue's one-way data flow, making the app easier to understand and debug.

How does a child component send data to its parent in Vue?

A By directly changing the parent's data

B By using <code>v-model</code> on the child

C By emitting an event with <code>emit</code>

D By importing the parent component

The child uses emit to send events to the parent, which can include data.

In Vue 3 Composition API, where do you get the emit function?

A As the second argument of <code>setup()</code>

B From <code>this.$emit</code>

C As the first argument of <code>setup()</code>

D From <code>props</code>

In setup(props, { emit }), emit is the second argument.

How does the parent listen to a child's emitted event named 'update'?

A <code>&lt;Child :update="handler" /&gt;</code>

B <code>&lt;Child @update="handler" /&gt;</code>

C <code>&lt;Child v-model="handler" /&gt;</code>

D <code>&lt;Child emit-update="handler" /&gt;</code>

The parent listens with @update="handler" on the child component.

Why should child components not directly modify parent data?

A It breaks Vue's one-way data flow and makes debugging harder

B It is faster to emit events

C Vue does not allow child components to access parent data

D It causes syntax errors

Direct modification breaks the one-way data flow and can cause unpredictable bugs.

Which Vue feature helps keep components loosely coupled during communication?

A Using <code>ref</code> in parent

B Direct data binding from child to parent

C Global variables

D Events emitted by child components

Events allow communication without tight coupling between components.

Explain how a child component communicates with its parent using events in Vue 3 Composition API.

Think about how setup() parameters and event listeners work together.

Why is event-based communication between child and parent components recommended in Vue?

Consider Vue's design principles about data flow and component independence.