parent.vue
<template>
<input :type="computedType"/>
</template>
<script setup>
import { ref, computed } from 'vue';
const props = defineProps({
type: {
required: false,
type: String,
default: 'text',
},
});
const showPassword = ref(false);
const computedType = computed(() => {
if (props.type === 'password') {
return showPassword.value ? 'text' : 'password';
}
return props.type;
});
</script>
<script>
export default {
data() {
return {
uuid: getRandomUuid(),
}
}
}
</script>
child.vue
<template>
<input :type="computedType"/>
</template>
<script>
import Parent from '~/components/parent.vue'
export default {
extends: Parent
}
</script>
In Vue3, I have a child.vue component which is inherited from parent.vue, I defined a computedType computed attribute in parent.vue, but it's missing in child.vue, however, uuid which is defined in parent.vue is accessible in child.vue.
[Vue warn]: Property "computedType" was accessed during render but is not defined on instance.
How to get computedType and any other attributes defined in <script setup> of parent.vue in child.vue?
Really appreciate any help provided!
update:
Only if I define all the attributes in <script>(but not in setup()) instead of <script setup>, they could be accessible
There are a few specific instances where you can have more than one script tag, and they are all outlined here in the documentation. Still, besides those 3 specific use cases, you shouldn't use more than one script tag. Your case of a separate script tag for one data variable is not a valid use case.
I recommend writing the component entirely with the options API (the only API that supports the "extends" option), or writing entirely with the composition API where you would use composable functions to effectively extend your component
defineExpose({computedType});
try this
Related
Below is a code for a header and a body (different components). How do you call the continue function of the component 2 and pass a parameter when you are inside component 1, using composition API way...
Component 2:
export default {
setup() {
const continue = (parameter1) => {
// do stuff here
}
return {
continue
}
}
}
One way to solve this is to use events for parent-to-child communication, combined with template refs, from which the child method can be directly called.
In ComponentB.vue, emit an event (e.g., named continue-event) that the parent can listen to. We use a button-click to trigger the event for this example:
<!-- ComponentB.vue -->
<script>
export default {
emits: ['continue-event'],
}
</script>
<template>
<h2>Component B</h2>
<button #click="$emit('continue-event', 'hi')">Trigger continue event</button>
</template>
In the parent, use a template ref on ComponentA.vue to get a reference to it in JavaScript, and create a function (e.g., named myCompContinue) to call the child component's continueFn directly.
<!-- Parent.vue -->
<script>
import { ref } from 'vue'
export default {
⋮
setup() {
const myComp = ref()
const myCompContinue = () => myComp.value.continueFn('hello from B')
return {
myComp,
myCompContinue,
}
},
}
</script>
<template>
<ComponentA ref="myComp" />
⋮
</template>
To link the two components in the parent, use the v-on directive (or # shorthand) to set myCompContinue as the event handler for ComponentB.vue's continue-event, emitted in step 1:
<template>
⋮
<ComponentB #continue-event="myCompContinue" />
</template>
demo
Note: Components written with the Options API (as you are using in the question) by default have their methods and props exposed via template refs, but this is not true for components written with <script setup>. In that case, defineExpose would be needed to expose the desired methods.
It seems like composition API makes everything a lot harder to do with basically no or little benefit. I've recently been porting my app to composition API and it required complete re-architecture, loads of new code and complexity. I really don't get it, seems just like a massive waste of time. Does anyone really think this direction is good ?
Here is how I solved it with script setup syntax:
Parent:
<script setup>
import { ref } from 'vue';
const childComponent = ref(null);
const onSave = () => {
childComponent.value.saveThing();
};
</script>
<template>
<div>
<ChildComponent ref="childComponent" />
<SomeOtherComponent
#save-thing="onSave"
/>
</div>
</template>
ChildComponent:
<script setup>
const saveThing = () => {
// do stuff
};
defineExpose({
saveThing,
});
</script>
It doesn't work without defineExpose. Besides that, the only trick is to create a ref on the component in which you are trying to call a function.
In the above code, it doesn't work to do #save-thing="childComponent.saveThing", and it appears the reason is that the ref is null when the component initially mounts.
I know that in Vue parents should update the children through props and children should update their parents through events.
Assume this is my parent component .vue file:
<template>
<div>
<my-child-component :category="category"></my-child-component>
</div>
</template>
<script>
export default {
data: {
return {
category: 'Test'
}
}
}
</script>
When I update the category data in this component, it will also update the category props in my-child-component.
Now, when I want to use Vue in Laravel, I usually use an inline template and pass the value from the blade directly to my components (as for example also suggested at https://stackoverflow.com/a/49299066/2311074).
So the above example my my-parent-component.blade.php could look like this:
#push('scripts')
<script src="/app.js"></script>
#endpush
<my-parent-component inline-template>
<my-child-component :category="{{ $category }}"></my-child-component>
</my-parent-component>
But now my-parent-component is not aware about the data of category. Basically only the child knows the category and there is no communication between parent and child about it.
How can I pass the data from blade without breaking the parent and child communication?
I just had to pass the category to the inline-template component through props like this:
#push('scripts')
<script src="/app.js"></script>
#endpush
<my-parent-component :initcategory="{$category}}" inline-template>
<my-child-component v-model="category"></my-child-component>
</my-parent-component>
In my-parent-component I had to set the props and initialize is using the create method:
export default {
props: {
initcategory: '',
},
data() {
return {
category: '',
};
},
created(){
this.category = this.initcategory;
}
}
Now my my-parent-component is fully aware of the category and it can communicate to the child using props and $emit as usual.
Your reference to this answer is different altogether from what you are looking for!
He's binding the :userId prop of the example component but not the parent component or in simple words: Any template using the example vue can either pass a string prop or bind :userId prop to a string variable. Following is similar:
<example :userId="{{ Auth::user()->id }}"></example>
OR
<example :userId="'some test string'"></example>
So you should rather assign {{ $category }} to a data variable but rather binds to a child component prop which will have no effect on the parent.
In the following snippet you're only binding the string but rather a data key:
<my-child-component :category="{{ $category }}"></my-child-component>
Update
See the following example which will change the h1 title after 3 seconds
// HelloWorld.vue
<template>
<app-name :name="appName" #appNameChanged="appName = $event"></app-name>
</template>
<script>
export default {
props: ['name'],
data() {
return {
appName: null
}
},
mounted() {
// NOTE: since Strings are immutable and thus will assign the value while objects and arrays are copied by reference
// the following is just for the purpose of understanding how binding works
this.appName = this.name;
}
}
</script>
The template which renders the app title or you can say the child component
// AppName.vue
<template>
<h1>{{ name }}</h1>
</template>
<script>
export default {
props: ['name'],
mounted() {
setTimeout(() => {
this.$emit('appNameChanged', 'Change App')
}, 3000);
}
}
</script>
And here's how it is being used in the welcome.blade.php
<div id="app">
<hello-world :name="'Laravel App'"></hello-world>
</div>
I am terribly new to Vue, so forgive me if my terminology is off. I have a .NET Core MVC project with small, separate vue pages. On my current page, I return a view from the controller that just has:
#model long;
<div id="faq-category" v-bind:faqCategoryId="#Model"></div>
#section Scripts {
<script src="~/scripts/js/faqCategory.js"></script>
}
Where I send in the id of the item this page will go grab and create the edit form for. faqCategory.js is the compiled vue app. I need to pass in the long parameter to the vue app on initialization, so it can go fetch the full object. I mount it with a main.ts like:
import { createApp } from 'vue'
import FaqCategoryPage from './FaqCategoryPage.vue'
createApp(FaqCategoryPage)
.mount('#faq-category');
How can I get my faqCategoryId into my vue app to kick off the initialization and load the object? My v-bind attempt seems to not work - I have a #Prop(Number) readonly faqCategoryId: number = 0; on the vue component, but it is always 0.
My FaqCategoryPAge.vue script is simply:
<script lang="ts">
import { Options, Vue } from "vue-class-component";
import { Prop } from 'vue-property-decorator'
import Card from "#/Card.vue";
import axios from "axios";
import FaqCategory from "../shared/FaqCategory";
#Options({
components: {
Card,
},
})
export default class FaqCategoryPage extends Vue {
#Prop(Number) readonly faqCategoryId: number = 0;
mounted() {
console.log(this.faqCategoryId);
}
}
</script>
It seems passing props to root instance vie attributes placed on element the app is mounting on is not supported
You can solve it using data- attributes easily
Vue 2
const mountEl = document.querySelector("#app");
new Vue({
propsData: { ...mountEl.dataset },
props: ["message"]
}).$mount("#app");
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
<div id="app" data-message="Hello from HTML">
{{ message }}
</div>
Vue 3
const mountEl = document.querySelector("#app");
Vue.createApp({
props: ["message"]
}, { ...mountEl.dataset }).mount("#app");
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/3.0.0/vue.global.js"></script>
<div id="app" data-message="Hello from HTML">
{{ message }}
</div>
Biggest disadvantage of this is that everything taken from data- attributes is a string so if your component expects something else (Number, Boolean etc) you need to make conversion yourself.
One more option of course is pushing your component one level down. As long as you use v-bind (:counter), proper JS type is passed into the component:
Vue.createApp({
components: {
MyComponent: {
props: {
message: String,
counter: Number
},
template: '<div> {{ message }} (counter: {{ counter }}) </div>'
}
},
}).mount("#app");
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/3.0.0/vue.global.js"></script>
<div id="app">
<my-component :message="'Hello from HTML'" :counter="10" />
</div>
Just an idea (not a real problem)
Not really sure but it can be a problem with Props casing
HTML attribute names are case-insensitive, so browsers will interpret any uppercase characters as lowercase. That means when you're using in-DOM templates, camelCased prop names need to use their kebab-cased (hyphen-delimited) equivalents
Try to change your MVC view into this:
<div id="faq-category" v-bind:faq-category-id="#Model"></div>
Further to Michal Levý's answer regarding Vue 3, you can also implement that pattern with a Single File Component:
app.html
<div id="app" data-message="My Message"/>
app.js
import { createApp } from 'vue';
import MyComponent from './my-component.vue';
const mountEl = document.querySelector("#app");
Vue.createApp(MyComponent, { ...mountEl.dataset }).mount("#app");
my-component.vue
<template>
{{ message }}
</template>
<script>
export default {
props: {
message: String
}
};
</script>
Or you could even grab data from anywhere on the parent HTML page, eg:
app.html
<h1>My Message</h1>
<div id="app"/>
app.js
import { createApp } from 'vue';
import MyComponent from './my-component.vue';
const message = document.querySelector('h1').innerText;
Vue.createApp(MyComponent, { message }).mount("#app");
my-component.vue
<template>
{{ message }}
</template>
<script>
export default {
props: {
message: String
}
};
</script>
To answer TheStoryCoder's question: you would need to use a data prop. My answers above demonstrate how to pass a value from the parent DOM to the Vue app when it is mounted. If you wanted to then change the value of message after it was mounted, you would need to do something like this (I've called the data prop myMessage for clarity, but you could also just use the same prop name message):
<template>
{{ myMessage }}
<button #click="myMessage = 'foo'">Foo me</button>
</template>
<script>
export default {
props: {
message: String
},
data() {
return {
myMessage: this.message
}
}
};
</script>
So I'm not at all familiar with .NET and what model does, but Vue will treat the DOM element as a placeholder only and it does not extend to it the same functionality as the components within the app have.
so v-bind is not going to work, even without the value being reactive, the option is not there to do it.
you could try a hack to access the value and assign to a data such as...
const app = Vue.createApp({
data(){
return {
faqCategoryId: null
}
},
mounted() {
const props = ["faqCategoryId"]
const el = this.$el.parentElement;
props.forEach((key) => {
const val = el.getAttribute(key);
if(val !== null) this[key] = (val);
})
}
})
app.mount('#app')
<script src="https://unpkg.com/vue#3.0.0-rc.11/dist/vue.global.prod.js"></script>
<div id="app" faqCategoryId="12">
<h1>Faq Category Id: {{faqCategoryId}}</h1>
</div>
where you get the value from the html dom element, and assign to a data. The reason I'm suggesting data instead of props is that props are setup to be write only, so you wouldn't be able to override them, so instead I've used a variable props to define the props to look for in the dom element.
Another option
is to use inject/provide
it's easier to just use js to provide the variable, but assuming you want to use this in an mvc framework, so that it is managed through the view only. In addition, you can make it simpler by picking the exact attributes you want to pass to the application, but this provides a better "framework" for reuse.
const mount = ($el) => {
const app = Vue.createApp({
inject: {
faqCategoryId: {
default: 'optional'
},
},
})
const el = document.querySelector($el)
Object.keys(app._component.inject).forEach(key => {
if (el.getAttribute(key) !== null) {
app.provide(key, el.getAttribute(key))
}
})
app.mount('#app')
}
mount('#app')
<script src="https://unpkg.com/vue#3.0.0-rc.11/dist/vue.global.prod.js"></script>
<div id="app" faqCategoryId="66">
<h1>Faq Category Id: {{faqCategoryId}}</h1>
</div>
As i tried in the following example
https://codepen.io/boussadjra/pen/vYGvXvq
you could do :
mounted() {
console.log(this.$el.parentElement.getAttribute("faqCategoryId"));
}
All other answers might be valid, but for Vue 3 the simple way is here:
import {createApp} from 'vue'
import rootComponent from './app.vue'
let rootProps = {};
createApp(rootComponent, rootProps)
.mount('#somewhere')
Let's say I have a main Vue instance that has child components. Is there a way of calling a method belonging to one of these components from outside the Vue instance entirely?
Here is an example:
var vm = new Vue({
el: '#app',
components: {
'my-component': {
template: '#my-template',
data: function() {
return {
count: 1,
};
},
methods: {
increaseCount: function() {
this.count++;
}
}
},
}
});
$('#external-button').click(function()
{
vm['my-component'].increaseCount(); // This doesn't work
});
<script src="http://vuejs.org/js/vue.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="app">
<my-component></my-component>
<br>
<button id="external-button">External Button</button>
</div>
<template id="my-template">
<div style="border: 1px solid; padding: 5px;">
<p>A counter: {{ count }}</p>
<button #click="increaseCount">Internal Button</button>
</div>
</template>
So when I click the internal button, the increaseCount() method is bound to its click event so it gets called. There is no way to bind the event to the external button, whose click event I am listening for with jQuery, so I'll need some other way to call increaseCount.
EDIT
It seems this works:
vm.$children[0].increaseCount();
However, this is not a good solution because I am referencing the component by its index in the children array, and with many components this is unlikely to stay constant and the code is less readable.
In the end I opted for using Vue's ref directive. This allows a component to be referenced from the parent for direct access.
E.g.
Have a component registered on my parent instance:
var vm = new Vue({
el: '#app',
components: { 'my-component': myComponent }
});
Render the component in template/html with a reference:
<my-component ref="foo"></my-component>
Now, elsewhere I can access the component externally
<script>
vm.$refs.foo.doSomething(); //assuming my component has a doSomething() method
</script>
See this fiddle for an example: https://jsfiddle.net/0zefx8o6/
(old example using Vue 1: https://jsfiddle.net/6v7y6msr/)
Edit for Vue3 - Composition API
The child-component has to return the function in setup you want to use in the parent-component otherwise the function is not available to the parent.
Note: <sript setup> doc is not affacted, because it provides all the functions and variables to the template by default.
You can set ref for child components then in parent can call via $refs:
Add ref to child component:
<my-component ref="childref"></my-component>
Add click event to parent:
<button id="external-button" #click="$refs.childref.increaseCount()">External Button</button>
var vm = new Vue({
el: '#app',
components: {
'my-component': {
template: '#my-template',
data: function() {
return {
count: 1,
};
},
methods: {
increaseCount: function() {
this.count++;
}
}
},
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
<div id="app">
<my-component ref="childref"></my-component>
<button id="external-button" #click="$refs.childref.increaseCount()">External Button</button>
</div>
<template id="my-template">
<div style="border: 1px solid; padding: 2px;" ref="childref">
<p>A counter: {{ count }}</p>
<button #click="increaseCount">Internal Button</button>
</div>
</template>
For Vue2 this applies:
var bus = new Vue()
// in component A's method
bus.$emit('id-selected', 1)
// in component B's created hook
bus.$on('id-selected', function (id) {
// ...
})
See here for the Vue docs.
And here is more detail on how to set up this event bus exactly.
If you'd like more info on when to use properties, events and/ or centralized state management see this article.
See below comment of Thomas regarding Vue 3.
You can use Vue event system
vm.$broadcast('event-name', args)
and
vm.$on('event-name', function())
Here is the fiddle:
http://jsfiddle.net/hfalucas/wc1gg5v4/59/
A slightly different (simpler) version of the accepted answer:
Have a component registered on the parent instance:
export default {
components: { 'my-component': myComponent }
}
Render the component in template/html with a reference:
<my-component ref="foo"></my-component>
Access the component method:
<script>
this.$refs.foo.doSomething();
</script>
Say you have a child_method() in the child component:
export default {
methods: {
child_method () {
console.log('I got clicked')
}
}
}
Now you want to execute the child_method from parent component:
<template>
<div>
<button #click="exec">Execute child component</button>
<child-cmp ref="child"></child_cmp> <!-- note the ref="child" here -->
</div>
</template>
export default {
methods: {
exec () { //accessing the child component instance through $refs
this.$refs.child.child_method() //execute the method belongs to the child component
}
}
}
If you want to execute a parent component method from child component:
this.$parent.name_of_method()
NOTE: It is not recommended to access the child and parent component like this.
Instead as best practice use Props & Events for parent-child communication.
If you want communication between components surely use vuex or event bus
Please read this very helpful article
This is a simple way to access a component's methods from other component
// This is external shared (reusable) component, so you can call its methods from other components
export default {
name: 'SharedBase',
methods: {
fetchLocalData: function(module, page){
// .....fetches some data
return { jsonData }
}
}
}
// This is your component where you can call SharedBased component's method(s)
import SharedBase from '[your path to component]';
var sections = [];
export default {
name: 'History',
created: function(){
this.sections = SharedBase.methods['fetchLocalData']('intro', 'history');
}
}
Using Vue 3:
const app = createApp({})
// register an options object
app.component('my-component', {
/* ... */
})
....
// retrieve a registered component
const MyComponent = app.component('my-component')
MyComponent.methods.greet();
https://v3.vuejs.org/api/application-api.html#component
Here is a simple one
this.$children[indexOfComponent].childsMethodName();
I am not sure is it the right way but this one works for me.
First import the component which contains the method you want to call in your component
import myComponent from './MyComponent'
and then call any method of MyCompenent
myComponent.methods.doSomething()
Declare your function in a component like this:
export default {
mounted () {
this.$root.$on('component1', () => {
// do your logic here :D
});
}
};
and call it from any page like this:
this.$root.$emit("component1");
If you're using Vue 3 with <script setup> sugar, note that internal bindings of a component are closed (not visible from outside the component) and you must use defineExpose(see docs) to make them visible from outside. Something like this:
<script setup lang="ts">
const method1 = () => { ... };
const method2 = () => { ... };
defineExpose({
method1,
method2,
});
</script>
Since
Components using are closed by default
Sometimes you want to keep these things contained within your component. Depending on DOM state (the elements you're listening on must exist in DOM when your Vue component is instantiated), you can listen to events on elements outside of your component from within your Vue component. Let's say there is an element outside of your component, and when the user clicks it, you want your component to respond.
In html you have:
Launch the component
...
<my-component></my-component>
In your Vue component:
methods() {
doSomething() {
// do something
}
},
created() {
document.getElementById('outsideLink').addEventListener('click', evt =>
{
this.doSomething();
});
}
I have used a very simple solution. I have included a HTML element, that calls the method, in my Vue Component that I select, using Vanilla JS, and I trigger click!
In the Vue Component, I have included something like the following:
<span data-id="btnReload" #click="fetchTaskList()"><i class="fa fa-refresh"></i></span>
That I use using Vanilla JS:
const btnReload = document.querySelector('[data-id="btnReload"]');
btnReload.click();
I am building a form framework in vue. I have components for each field type. Each field type component uses this.$emit to communicate changes with the parent component.
I am able to trigger events in the parent component using v-on directives as follows:
<template>
<div v-if="fieldsLoaded">
<form-select :field="fields.title" v-on:updated="validate" ></form-select>
<form-input :field="fields.first_name" v-on:updated="validate" ></form-input>
</div>
</template>
However, I don't want to have to manually specify that every component should trigger the validate method individually.
How can I have the parent component listen for the updated emit across all its child components?
Edit: I'm looking for something like the below, though $on only catches emits that occur within the same component, rather than its children
created: function(){
this.$on('updated',validate)
}
The best way is to use event bus or even better in my opinion vuex.
For the first case take a look here
For the second here
With event bus you can emit an event, and listen to that event whenever you want(at parent,child even in the same component)
Vuex It serves as a centralized store for all the components in an application and you can have properties in that store,and you can use and manipulate them.
Example with event Bus:
main.js:
import Vue from 'vue'
import App from './App.vue'
export const eventBus = new Vue();
new Vue({
el: '#app',
render: h => h(App)
})
User Component
<template>
<button #click="clicked">Click me to create event</button>
</template>
<script>
import { eventBus } from './main'
export default {
name: 'User',
methods: {
clicked() {
eventBus.$emit('customEvent', 'a text to pass')
}
}
}
</script>
Admin component
<template>
<p>The message from event is: {{message}}</p>
</template>
<script>
import { eventBus } from './main'
export default {
name: 'Admin',
data: () => ({
message: ''
})
created() {
eventBus.$on('customEvent', dataPassed => {
this.message = dataPassed
}
}
}
</script>
Take a look to this tutorial to learn Vuex
For your case you can use v-model like following:
<template>
<div v-if="fieldsLoaded">
<form-select v-model="fields.title" :validate="validate" ></form-select>
<form-input v-model="fields.first_name" :validate="validate" ></form-input>
</div>
</template>
v-model is essentially syntax sugar for updating data on user input events.
<input v-model="something">
is just syntactic sugar for:
<input v-bind:value="something" v-on:input="something = $event.target.value">
You can pass a prop : value in the child components, and before changing input field call a function to validate which is also passed as a prop.
Vue.component('form-select', {
props: ['options', 'value', 'onChange', 'validate'], //Added one more prop
template: '#your-template',
mounted: function () {
},
methods: {
change (opt) {
if (this.validate !== undefined) {
var isValid = this.validate(this.value)
if(!isValid) return;
}
this.$emit('input', opt)
},
},
})