Can VueJS capture events emitted by a group of child components simultaneously?

Question

Can VueJS capture events emitted by a group of child components simultaneously?

I have a parent component that contains several child components.

<grid>
   <cell></cell>
   <cell></cell>
   <cell></cell>
</grid>

The child components emit an event with a payload indicating they are being edited: this.$emit('editing', cellId)

Instead of using root listeners like

<cell @editing="do something"></cell>

or EventBus.$on('editing'), I want to avoid using this.$root.$on('editing').

However, as the parent component, how can I listen for the 'editing' event when the parent component is mounted?

mounted: function(){
    this.$on('editing', doSomething)
}

Why am I unable to add a listener when the parent component is mounted?

javascript vue.js vuejs2 vue-component

Answer 1

Answer №1

The key distinction that may have eluded you can be found in the Custom Events section:

Moreover, a parent component has the ability to heed events emitted from a child component through direct use of v-on within the template where the child component is placed.

It's important to note that using $on to listen to events emitted by children is not permissible. The correct method mandates employing v-on directly in the template, as exemplified below.

This implies that communication between child and parent components transpires via a directive, utilizing the v-on (or @edit) approach.

Your provided example

mounted: function(){
    this.$on('editing',dosomething)
}

will fail to yield results. As per the emit documentation, it clarifies:

Initiate an event on the present instance.

This indicates that when operating within the same component, you are able to utilize this.$on successfully. However, for usage at the parent level, incorporation of the inline directive is essential for successful binding; otherwise, the process will fall short.

Additionally, keep in mind that emits functionality serves solely for a single step, whereby the parent can capture it. Should the need arise for emitting from subchild -> child -> parent, you must receive the event (via inline binding) from subchild within child, and subsequently emit it again to reach the parent level.

If the scenario extends beyond the child-parent arena, resorting to what is referred to as a global bus is advisable. Essentially, this streamlines all operations to a singular instance, which both emits and listens for all events. Consequently, connections are no longer confined to child-parent dynamics but instead converge onto a shared system, allowing unrestricted application across all your components.

In essence - relying on mounted for listening purposes won't yield favorable outcomes. Trust this exegesis guides you accordingly :)

Answer 2

The key distinction that may have eluded you can be found in the Custom Events section:

Moreover, a parent component has the ability to heed events emitted from a child component through direct use of v-on within the template where the child component is placed.

It's important to note that using $on to listen to events emitted by children is not permissible. The correct method mandates employing v-on directly in the template, as exemplified below.

This implies that communication between child and parent components transpires via a directive, utilizing the v-on (or @edit) approach.

Your provided example

mounted: function(){
    this.$on('editing',dosomething)
}

will fail to yield results. As per the emit documentation, it clarifies:

Initiate an event on the present instance.

This indicates that when operating within the same component, you are able to utilize this.$on successfully. However, for usage at the parent level, incorporation of the inline directive is essential for successful binding; otherwise, the process will fall short.

Additionally, keep in mind that emits functionality serves solely for a single step, whereby the parent can capture it. Should the need arise for emitting from subchild -> child -> parent, you must receive the event (via inline binding) from subchild within child, and subsequently emit it again to reach the parent level.

If the scenario extends beyond the child-parent arena, resorting to what is referred to as a global bus is advisable. Essentially, this streamlines all operations to a singular instance, which both emits and listens for all events. Consequently, connections are no longer confined to child-parent dynamics but instead converge onto a shared system, allowing unrestricted application across all your components.

In essence - relying on mounted for listening purposes won't yield favorable outcomes. Trust this exegesis guides you accordingly :)

Answer 3

Answer №2

One important distinction to make is between listening to individual children versus listening to the EventBus:

When you emit an event using this.$emit('event'), the event will only be triggered for the parent component.
On the other hand, if you use the EventBus like EventBus.$emit('event'), the event will be broadcasted to all components.

Both approaches have their advantages and disadvantages; EventBus may clutter components with unnecessary events (event pollution), while using parent event emitters may not always be as elegant as EventBus.
It ultimately comes down to your preference and needs in deciding which approach to take.

Answer 4

One important distinction to make is between listening to individual children versus listening to the EventBus:

When you emit an event using this.$emit('event'), the event will only be triggered for the parent component.
On the other hand, if you use the EventBus like EventBus.$emit('event'), the event will be broadcasted to all components.

Both approaches have their advantages and disadvantages; EventBus may clutter components with unnecessary events (event pollution), while using parent event emitters may not always be as elegant as EventBus.
It ultimately comes down to your preference and needs in deciding which approach to take.

Answer 5

Answer №3

After encountering a similar issue, I found a solution. As others have mentioned, when you want to attach an event listener from a parent to a child component in Vue.js, you need to use v-on. This is because the child component is the one actually running the callback function when the event occurs.

Inside the child component, you can emit the event using

this.$parent.$emit('event-name');

In the parent component, you can listen for this emitted event by using:

mounted: function() {
    this.$on('event-name', function() {console.log('test')});
}

By following the above steps, you can trigger the event in the parent component and then listen for it using $on. This allows you to establish communication between parent and child components in Vue.js.

Answer 6

After encountering a similar issue, I found a solution. As others have mentioned, when you want to attach an event listener from a parent to a child component in Vue.js, you need to use v-on. This is because the child component is the one actually running the callback function when the event occurs.

Inside the child component, you can emit the event using

this.$parent.$emit('event-name');

In the parent component, you can listen for this emitted event by using:

mounted: function() {
    this.$on('event-name', function() {console.log('test')});
}

By following the above steps, you can trigger the event in the parent component and then listen for it using $on. This allows you to establish communication between parent and child components in Vue.js.

Can VueJS capture events emitted by a group of child components simultaneously?

Answer №1

Answer №2

Answer №3

Similar questions

Blank advertisements displayed on WordPress due to Google AdSense malfunction

Retrieving Information from Ajax Call Using Python

javascript floating point calculation

What is the best way to ensure that only one div is toggled at a time while using the toggle class function?

Is it possible to have multiple single page applications within a single app, or to combine history and hash routing in the same app environment?

Button Click Does Not Trigger Bootstrap Modal Display

Swapping a value within an array and moving it to a new position

What is the purpose of having a constructor in Typescript when an interface is already used for a class?

Using jQuery UI Datepicker and AngularJS to create a custom dashboard in Umbraco platform

The custom created THREE.Curve is not rendering correctly

A tutorial on preventing backbone.js from automatically adding /# when a dialog is closed

What steps should I take to resolve the "StrictMode has found deprecated findDOMNode" error?

Tips for transforming a table column into an input field to retrieve the value and id of the field?

Executing JavaScript functions within Vue JS components

How can I stop a table from resizing in Tailwind CSS?

Ways to send a variable to a component through history.replace

How can you convert Promise.all to a single Promise?

Generating arrays and datasets using the power of JavaScript and jQuery

Vue.js - experiencing issues with conditional styling not functioning as expected

Finding an Element by its Class Name