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Data from Blade File not rendering in Vue Component

I am working in Laravel Blade and trying to convert some blade files to vue components. I have a property in my blade file of pagetitle. I am trying to get the dynamically created page title to render on the screen from my vue component and not blade. But in my vue console, data comes back as "". Not sure why the data is carrying over.
Header.vue
<template>
<div>
<p title="page-title">{{pageTitle}}</p>
</div>
</template>
<script>
export default {
props: {
pageTitle: {
type: String
}
}
}
</script>
app.js
window.Vue = require('vue');
import Header from './components/Header';
Vue.component('header', Header);
const app = new Vue({
el: '#app',
});
main.blade.php
<div id="app">
<header :page-title="{{$pageTitle}}"></header>
</div>
header.blade.php //where page title is being pulled from
<title>
{{ $pageTitle ?? 'Default Page Title' }}
</title>

In your Header.vue file you are defining pageTitle as a data property, while it should be defined as a prop, since you are actually providing it as a property on the header component.
props: {
pageTitle: {
type: String
}
}

There already exists an HTML element called header, I suggest you rename your component. Your component is missing a props attribute to take input from blade:
Pagetitle.vue:
<template>
<div>
<p title="page-title">{{ this.pageTitle}}</p>
</div>
</template>
<script>
export default {
props: ['title'],
data() {
return {
pageTitle: '',
};
},
created() {
this.pageTitle = this.title
}
}
</script>
We created a title property. When the component is created, we set the component's pageTitle to the title given in main.blade.php.
app.js
window.Vue = require('vue');
import Pagetitle from './components/Pagetitle';
Vue.component('pagetitle', Pagetitle);
const app = new Vue({
el: '#app',
});
main.blade.php
<div id="app">
<pagetitle :title="foo bar"></pagetitle>
</div>
https://v2.vuejs.org/v2/guide/components-props.html

How load template for a VueJS component dynamically?

I want to load the template for a VueJS component dynamically,
I tried this code:
<template>
<div>
<default></default>
<div v-component="{currentView}"></div>
</div>
</template>
<script>
import { Component, Vue, Watch } from "vue-property-decorator";
//import App from './App.vue'
import VueFormWizard from "vue-form-wizard";
#Component({})
export default class detail extends Vue {}
window.addEventListener("load", () => {
window.onload = function() {
//Create the 'default' component
Vue.component("default", {
template: "<div>This should be replaced (and will be in 2 seconds)</div>"
});
//Create the parent ViewModel
var vm = new Vue({
el: "body",
data: {
currentView: "default"
}
});
//Pretend to load the data from the server
//This would actually be $.get("/url", data, function(){...});
window.setTimeout(function() {
//Create the new component using the template we received
Vue.component("BoardFeed", {
template:
'<div>Template returned from server, what I really want</div><br>And directives work too:<div v-repeat="items">{{$value}}</div>',
data: function() {
return {
items: [1, 2, 3]
};
}
});
//And then change the page to that component
vm.currentView = "BoardFeed";
}, 2000);
};
});
</script>
<style>
textarea {
width: 100%;
min-height: 100px;
}
</style>
but I get error:
[Vue warn]: Property or method "currentView" is not defined on the
instance but referenced during render. Make sure that this property is
reactive, either in the data option, or for class-based components, by
initializing the property. See:
https://v2.vuejs.org/v2/guide/reactivity.html#Declaring-Reactive-Properties.
How can I fix it?

print Component B inside component A - vue.js

Using Vue.js,
How to create componentA that gets componentB as a prop, and print it inside of it?
example:
index.vue
<template>
<div>
<componentA :componentPlaceHolder="componentB"></componentA>
</div>
</template>
<script>
import componentA from './compnentA.vue';
import componentB from './componentB.vue'
export default {
name: 'index',
components: {componentA,componentB }
}
</script>
componentA.vue
<template>
<div>
{{componentPlaceHolder}}
</div>
</template>
<script>
export default {
name: 'componentA',
props: {
'componentPlaceHolder': {}
}
}
</script>

There are some issues to your implementation:
You have gotten the scope wrong: componentPlaceHolder lives in the parent scope, not in that of component A. Read: Compilation Scope.
Use :is (i.e. v-bind: is) for dynamic component binding. The data bound should reference the key of the component.
Since you are nested additional components in another component in the same context, that means you have to interweave the content. This is done by using slots, declared in <component-a>.
Avoid using case-sensitive DOM elements, use kebab case instead, i.e. <component-a> instead of <componentA>, since HTML elements are case-insensitive (<componentA> and <componenta> will be treated the same).
Here is the updated code:
<template>
<div>
<component-a>
<customComponent :is="componentPlaceHolder"></customComponent>
</component-a>
</div>
</template>
<script>
import componentA from './componentA.vue';
import componentB from './componentB.vue'
export default {
name: 'index',
components: {
'component-a': componentA,
'component-b': componentB
},
data: {
componentPlaceHolder: 'component-b'
}
}
</script>
And then in your componentA.vue:
<template>
<div>
<!-- Slot will interweave whatever that is found in <componentA> -->
<slot></slot>
</div>
</template>
<script>
export default {
name: 'componentA'
}
</script>
Proof-of-concept example
If in doubt, here is a live proof-of-concept example:
var componentA = {
template: '#component-a'
};
var componentB = {
template: '#component-b'
};
new Vue({
el: '#app',
components: {
'component-a': componentA,
'component-b': componentB
},
data: {
componentPlaceHolder: 'component-b'
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.3.3/vue.min.js"></script>
<div id="app">
<component-a>
<!-- DOM elements in here will be interweaved into <slot> -->
<customComponent :is="componentPlaceHolder"></customComponent>
</component-a>
</div>
<template id="component-a">
<div>
<p>I am component A</p>
<slot></slot>
</div>
</template>
<template id="component-b">
<p>I am component B</p>
</template>
Footnote:
The VueJS readme is exceptionally composed, and I suggest here are some things that you can read up on that is very relevant to your use case:
Compilation Scope
Dynamic Components
Content Distribution with Slots

Vue instance inside Vue instance

Sup people!
I got this HTML code here:
// index.html
<div data-init="component-one">
<...>
<div data-init="component-two">
<button #click="doSomething($event)">
</div>
</div>
This basically references a Vue instance inside another Vue instance if I understood everything correctly. The respective JS code is split up in two files and looks like this:
// componentOne.js
new Vue(
el: '[data-init="component-one"]',
data: {...},
methods: {...}
);
// componentTwo.js
new Vue(
el: '[data-init="component-two"]'
data: {...}
methods: {
doSomething: function(event) {...}
}
);
Now, the problem with this is, that doSomething from componentTwo never gets called.
But when I do some inline stuff, like {{ 3 + 3 }}, it gets computed like it should. So Vue knows there is something. And it also removes the #click element on page load.
I tried fiddling around with inline-template as well, but it doesn't really work as I'd expect it to in this situation. And I figured it isn't meant for this case anyway, so I dropped it again.
What would the correct approach be here? And how can I make this work the easiest way possible with how it's set up right now?
The Vue version we use is 2.1.8.
Cheers!

The problem is that you have two vue instances nested to each other.
If the elements are nested, then you should use the same instance or try components
https://jsfiddle.net/p16y2g16/1/
// componentTwo.js
var item = Vue.component('item',({
name:'item',
template:'<button #click="doSomething($event)">{{ message2 }</button>',
data: function(){
return{
message2: 'ddddddddddd!'
}},
methods: {
doSomething: function(event) {alert('s')}
}
}));
var app = new Vue({
el: '[data-init="component-one"]',
data: {
message: 'Hello Vue!'
}
});
<div data-init="component-one">
<button >{{ message }}</button>
<item></item>
</div>
Separate instances work if they are independant of each other.
as follows:
https://jsfiddle.net/p16y2g16/
var app = new Vue({
el: '[data-init="component-one"]',
data: {
message: 'Hello Vue!'
}
});
// componentTwo.js
var ddd = new Vue({
el: '[data-init="component-two"]',
data: {
message: 'ddddddddddd!'
},
methods: {
doSomething: function(event) {alert('s')}
}
});

But when I do some inline stuff, like {{ 3 + 3 }}, it gets computed like it should. So Vue knows there is something.
Because you have parent instance 'componentOne'. It activated Vue for this template. If you need to set another instance inside, you have to separate part of template. Example (it can lag in snippet!) .
Alternative
https://jsfiddle.net/qh8a8ebg/2/
// componentOne.js
new Vue({
el: '[data-init="component-one"]',
data: {
text: 'first'
},
methods: {}
});
// componentTwo.js
new Vue({
el: '[data-init="component-two"]',
data: {
text: 'second'
},
template: `<button #click="doSomething($event)">{{text}}</button>`,
methods: {
doSomething: function(event) {
console.log(event);
}
}
});
<script src="https://vuejs.org/js/vue.min.js"></script>
<div data-init="component-one">
{{text}}
</div>
<div data-init="component-two">
</div>

The button element inside component-two is referenced as a slot in Vue.
The evaluation of the #click directive value happens in the parent component (component-one, which host component-two). Therefor, you need to declare the click handler over there (over component-one).
If you want the handler to be handled inside component-two, you should declare a click directive for the slot element in it's (component-two) template, and pass the handler function, for instance, as a pop.
good luck.

You're doing everything right except you've nested the 2nd Vue instance inside the 1st. Just put it to the side and it will work as expected.
Vue ignores binding more than once to the same element to avoid infinite loops, which is the only reason it doesn't work nested.

Use vue-cli to create a webpack starter app. vue init app --webpack
Then, try to structure your components this way. Read more: https://v2.vuejs.org/v2/guide/components.html#What-are-Components
This is main.js
import Vue from 'vue'
import ComponentOne from './ComponentOne.vue'
import ComponentTwo from './ComponentTwo.vue'
new Vue({
el: '#app',
template: '<App/>',
components: {
ComponentOne,
ComponentTwo
}
})
This is ComponentOne.vue
<template>
<div class="user">
<div v-for="user in users">
<p>Username: {{ user.username }}</p>
</div>
</div>
</template>
<script>
export default {
data () {
return {
users: [
{username: 'Bryan'},
{username: 'Gwen'},
{username: 'Gabriel'}
]
}
}
}
</script>
This is ComponentTwo.vue
<template>
<div class="two">
Hello World
</div>
</template>
<script>
export default {
}
</script>

<div th:if="${msg.replyFloor}">
<div class="msg-lists-item-left">
<span class="msg-left-edit"
th:classappend=" ${msg.unreadCount == 0} ? 'msg-all-read' ">您在</span>
<span th:text="${msg.topic.title}"
class="msg-left-edit-res"
th:classappend=" ${msg.unreadCount == 0} ? 'msg-all-read' ">问题回答</span>
<span th:text="${msg.type.name}"
class="msg-left-edit "
th:classappend=" ${msg.unreadCount == 0} ? 'msg-all-read' ">帖子相关</span>
<span class="msg-left-edit-number" >
产生了<span th:text="${msg.unreadCount} ? : ${msg.unreadCount} + '条新' : ${msg.unreadCount} + '条' "
th:class="${msg.unreadCount} ? : 'number-inner':''">2132条</span>回复
</span>
</div>
<div class="msg-lists-item-right">
<span th:text="${msg.lastShowTime}">2017-8-10</span>
</div>
</div>

Call a Vue.js component method from outside the component

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();