Develop Reference

Vue bind child component data from parent

I need to bind my child component data (inputData) from parent component but it's not working i cannot find where is my mistake
app.js
let vm = new Vue({
el: "#app",
components: {
'modal-panel': modal,
'rich-select': richSelect,
'file-upload': uploader,
},
data(){ return {
isModalActive: false,
inputData: null
}} ,
methods: {
toggleModal(){
this.isModalActive = !this.isModalActive
},
modalData(){
this.inputData = 'Example Data'
}
}
});
Modal.vue
<template>
<input type="text" :value="inputData" >
</template>
export default {
name: 'modal',
props: ['inputData'],
mounted(){
console.log('modal Mounted')
}
};
inside my blade i'am calling modal component like this
<div class="container" id="app">
<modal-panel v-if="isModalActive" #close="toggleModal" :inputData="inputData"></modal-panel>
</div>
when i test that code all methods are working but inside Modal.vue input still not binding

You've to use the prop with kebab-case format as follows :
<modal-panel v-if="isModalActive" #close="toggleModal" :input-data="inputData"></modal-panel>

Is Vue's 'destroyed' method called on page refresh?

I am wondering if refreshing a page that runs a Vue app will trigger the Vue's .destroyed callback.
From what I observed in a Vue app that contains these simple lifecycle callbacks:
created() {
console.log(' created');
},
destroyed() {
console.log('destroyed')；
}
only 'created' is logged (not 'destroyed'). How can I check if the .destroyed callback has been executed?

I found the similar question and answer to it on stackoverflow
Do something before reload or close in vue.js
He/she basically explains that nothing is destroyed on page reload, you need to define
window.onbeforeunload = function(){
return "Are you sure you want to close the window?";
}
If you want to do something before a page refresh

As your question was
Is Vue's 'destroyed' method called on page refresh?
No, destroyed method called if your component's controller lost or you manually destroy, above example is for manually destroy.
I have found very good example in vuejs forum which uses externally this.$destroy() method.
new Vue({
el: '#app',
data() {
return {
value: 'will work until destroy'
};
},
methods: {
destroy() {
this.$destroy();
}
},
beforeDestroy() {
console.log('Main Vue destroyed')
}
})
var tmp = Vue.extend({
template: `
<div>
<span>{{ value }}</span>
<input v-model="value" />
</div>
`,
data() {
return {
value: 'always bind and work'
};
},
beforeDestroy() {
console.log('Mounted destroyed')
}
});
new tmp().$mount('#mount-point');
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.6.10/vue.js"></script>
<div id="app">
{{ value }}
<input v-model="value" />
<div id="mount-point"></div>
<button #click="destroy()">Destroy</button>
</div>
Reference
Another example. If component's control lost or removed then destroy method will be called of that component's
Vue.component('comp1', {
template: '<div>A custom component1!</div>',
destroyed(){
console.log('comp1 destroyed');
}
})
Vue.component('comp2', {
template: '<div>A custom component2!</div>',
destroyed(){
console.log('comp2 destroyed');
}
})
new Vue({
el: '#app',
data() {
return {
value: 1
};
},
methods: {
},
beforeDestroy() {
console.log('Main Vue destroyed')
}
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.6.10/vue.js"></script>
<div id="app">
<select v-model="value">
<option value="1">comp1</option>
<option value="2">comp2</option>
</select>
<comp1 v-if="value==1"></comp1>
<comp2 v-if="value==2"></comp2>
<button #click="destroy()">Destroy</button>
</div>

Dynamically changing props

On my app, I have multiple "upload" buttons and I want to display a spinner/loader for that specific button when a user clicks on it. After the upload is complete, I want to remove that spinner/loader.
I have the buttons nested within a component so on the file for the button, I'm receiving a prop from the parent and then storing that locally so the loader doesn't show up for all upload buttons. But when the value changes in the parent, the child is not getting the correct value of the prop.
App.vue:
<template>
<upload-button
:uploadComplete="uploadCompleteBoolean"
#startUpload="upload">
</upload-button>
</template>
<script>
data(){
return {
uploadCompleteBoolean: true
}
},
methods: {
upload(){
this.uploadCompleteBoolean = false
// do stuff to upload, then when finished,
this.uploadCompleteBoolean = true
}
</script>
Button.vue:
<template>
<button
#click="onClick">
<button>
</template>
<script>
props: {
uploadComplete: {
type: Boolean
}
data(){
return {
uploadingComplete: this.uploadComplete
}
},
methods: {
onClick(){
this.uploadingComplete = false
this.$emit('startUpload')
}
</script>

Fixed event name and prop name then it should work.
As Vue Guide: Custom EventName says, Vue recommend always use kebab-case for event names.
so you should use this.$emit('start-upload'), then in the template, uses <upload-button #start-upload="upload"> </upload-button>
As Vue Guide: Props says,
HTML attribute names are case-insensitive, so browsers will interpret
any uppercase characters as lowercase. That means when you’re using
in-DOM templates, camelCased prop names need to use their kebab-cased
(hyphen-delimited) equivalents
so change :uploadComplete="uploadCompleteBoolean" to :upload-complete="uploadCompleteBoolean"
Edit: Just noticed you mentioned data property=uploadingComplete.
It is easy fix, add one watch for props=uploadComplete.
Below is one simple demo:
Vue.config.productionTip = false
Vue.component('upload-button', {
template: `<div> <button #click="onClick">Upload for Data: {{uploadingComplete}} Props: {{uploadComplete}}</button>
</div>`,
props: {
uploadComplete: {
type: Boolean
}
},
data() {
return {
uploadingComplete: this.uploadComplete
}
},
watch: { // watch prop=uploadComplete, if change, sync to data property=uploadingComplete
uploadComplete: function (newVal) {
this.uploadingComplete = newVal
}
},
methods: {
onClick() {
this.uploadingComplete = false
this.$emit('start-upload')
}
}
})
new Vue({
el: '#app',
data() {
return {
uploadCompleteBoolean: true
}
},
methods: {
upload() {
this.uploadCompleteBoolean = false
// do stuff to upload, then when finished,
this.uploadCompleteBoolean = true
},
changeStatus() {
this.uploadCompleteBoolean = !this.uploadCompleteBoolean
}
}
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.16/vue.js"></script>
<div id="app">
<button #click="changeStatus()">Toggle Status {{uploadCompleteBoolean}}</button>
<p>Status: {{uploadCompleteBoolean}}</p>
<upload-button :upload-complete="uploadCompleteBoolean" #start-upload="upload">
</upload-button>
</div>

The UploadButton component shouldn't have uploadingComplete as local state (data); this just complicates the component since you're trying to mix the uploadComplete prop and uploadingComplete data.
The visibility of the spinner should be driven by the parent component through the prop, the button itself should not be responsible for controlling the visibility of the spinner through local state in response to clicks of the button.
Just do something like this:
Vue.component('upload-button', {
template: '#upload-button',
props: ['uploading'],
});
new Vue({
el: '#app',
data: {
uploading1: false,
uploading2: false,
},
methods: {
upload1() {
this.uploading1 = true;
setTimeout(() => this.uploading1 = false, Math.random() * 1000);
},
upload2() {
this.uploading2 = true;
setTimeout(() => this.uploading2 = false, Math.random() * 1000);
},
},
});
<script src="https://rawgit.com/vuejs/vue/dev/dist/vue.js"></script>
<div id="app">
<upload-button :uploading="uploading1" #click="upload1">Upload 1</upload-button>
<upload-button :uploading="uploading2" #click="upload2">Upload 2</upload-button>
</div>
<template id="upload-button">
<button #click="$emit('click')">
<template v-if="uploading">Uploading...</template>
<slot v-else></slot>
</button>
</template>

Your question seems little bit ambiguë, You can use watch in that props object inside the child component like this:
watch:{
uploadComplete:{
handler(val){
//val gives you the updated value
}, deep:true
},
}
by adding deep to true it will watch for nested properties in that object, if one of properties changed you ll receive the new prop from val variable
for more information : https://v2.vuejs.org/v2/api/#vm-watch
if not what you wanted, i made a real quick example,
check it out hope this helps : https://jsfiddle.net/K_Younes/64d8mbs1/

How can I change data value from one component to another component in Vue Js?

I am new in Vue Js. So, I am facing a problem to changes data value from another component.
I have a component A:
<template>
<div id="app">
<p v-on:click="test ()">Something</p>
</div>
</template>
import B from '../components/B.vue';
export default {
components: {
B
},
methods: {
test: function() {
B.data().myData = 124
B.data().isActive = true
console.log(B.data().myData);
console.log(B.data().isActive);
}
}
}
Component B:
export default {
data() {
return {
myData: 123,
isActive: false
}
}
}
It still component B data.
But it cannot be affected component B data. I want to data changes of component B from component A. How can I do that?
Please explain me in details. I have seen vue js props attribute but I don't understand.

You're looking for Vuex.
It's the centralized store for all the data in your applications.
Take a look at their documentation, it should be pretty straightforward.

You can pass down props to the component B. These props can be updated by the parent component. You can think of B as a stupid component that just renders what the parent tells it to rendern. Example:
// Component A
<template>
<div id="app">
<p v-on:click="test ()">Something</p>
<b data="myData" isActive="myIsActive"></b>
</div>
</template>
<script>
import B from '../components/B.vue';
export default {
components: {
B
},
data() {
return {
myData: 0,
myIsActive: false,
};
},
methods: {
test: function() {
this.myData = 123
this.myIsActive = true
}
}
}
</script>
// Component B
<template>
<div>{{ data }}{{ isActive }}</div>
</template>
<script>
export default {
props: {
data: Number,
isActive: Boolean
};
</script>

There are few ways...
if your components have a parent child relationship you can pass data values from parent into child.
If your want to communicate back to parent component when child component has changed something, you can use vuejs event emitter(custom event) to emit a event when data value change and that event can be listened in another component and do what you want.
If your components doesn't have a relationship, then you have to use use something else than above things. You can use two things.one is event bus, other one is state management library.for vue there is a official state management library called VueX.it is very easy to use.if you want to use something else than vuex, you can use it such as redux, mobx etc.
This documentation has everything what you want to know. I don't want to put any code, because of doc is very clear.
VueX is the most preferable way to do this! Very easy to use..
https://v2.vuejs.org/v2/guide/components.html

//component A
Vue.component('my-button', {
props: ['title'],
template: `<button v-on:click="$emit('add-value')">{{title}}</button>`
});
Vue.component('my-viewer', {
props: ['counter'],
template: `<button>{{counter}}</button>`
});
new Vue({
el: '#app',
data: {
counter: 0,
},
methods: {
doSomething: function() {
this.counter++;
}
}
})
Vue.component('blog-post', {
props: ['title'],
template: '<h3>{{ title }}</h3>'
});
//parent
new Vue({
el: '#blog-post-demo',
data: {
posts: [{
id: 1,
title: 'My journey with Vue'
},
{
id: 2,
title: 'Blogging with Vue'
},
{
id: 3,
title: 'Why Vue is so fun'
}
]
}
});
Vue.component('blog-post2', {
props: ['post'],
template: `
<div class="blog-post">
<h3>{{ post.title }}</h3>
<button v-on:click="$emit('enlarge-text')">
Enlarge text
</button>
<div v-html="post.content"></div>
</div>`
})
new Vue({
el: '#blog-posts-events-demo',
data: {
posts: [{
id: 1,
title: 'My journey with Vue'
},
{
id: 2,
title: 'Blogging with Vue'
},
{
id: 3,
title: 'Why Vue is so fun'
}
],
postFontSize: 1
},
methods: {
onEnlargeText: function() {
this.postFontSize++;
}
}
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
<p>Two components adding & viewing value</p>
<div id="app">
<my-button :title="'Add Value'" v-on:add-value="doSomething"></my-button>
<my-viewer :counter="counter"></my-viewer>
</div>
<br>
<br>
<p>Passing Data to Child Components with Props (Parent to Child)</p>
<div id="blog-post-demo">
<blog-post v-for="post in posts" v-bind:key="post.id" v-bind:title="post.title"></blog-post>
</div>
<p>Listening to Child Components Events (Child to Parent)</p>
<div id="blog-posts-events-demo">
<div :style="{ fontSize: postFontSize + 'em' }">
<blog-post2 v-for="post in posts" v-bind:key="post.id" v-bind:post="post" v-on:enlarge-text="onEnlargeText"></blog-post2>
</div>
</div>
First, you need a parent so two component can communicate. when my-button component is clicked triggers an event add-value that calls doSomething() function, then updates the value & show it to my-viewer component.
HTML
<!--PARENT-->
<div id="app">
<!--CHILD COMPONENTS-->
<my-button :title="'Add Value'" v-on:add-value="doSomething"></my-button>
<my-viewer :counter="counter"></my-viewer>
</div>
VUE.JS
//component A
Vue.component('my-button',{
props:['title'],
template:`<button v-on:click="$emit('add-value')">{{title}}</button>`
});
//Component B
Vue.component('my-viewer',{
props:['counter'],
template:`<button>{{counter}}</button>`
});
//Parent
new Vue({
el: '#app',
data:{
counter:0,
},
methods:{
doSomething:function(){
this.counter++;
}
}
})
This is base on Vue Components Guide
Passing Data to Child Components with Props (Parent to Child)
VUE.JS
//component (child)
//Vue component must come first, else it won't work
Vue.component('blog-post', {
/*Props are custom attributes you can register on a component. When a
value is passed to a prop attribute, it becomes a property on that
component instance*/
props: ['title'],
template: '<h3>{{ title }}</h3>'
});
//parent
new Vue({
el: '#blog-post-demo',
data: {
posts: [
{ id: 1, title: 'My journey with Vue' },
{ id: 2, title: 'Blogging with Vue' },
{ id: 3, title: 'Why Vue is so fun' }
]
}
});
HTML:
v-for will loop on posts and pass data to blog-post component
<div id="blog-post-demo">
<blog-post v-for="post in posts"
v-bind:key="post.id"
v-bind:title="post.title"></blog-post>
</div>
Listening to Child Components Events (Child to Parent)
HTML
You must first register the event by v-on:enlarge-text="onEnlargeText" to use $emit and make sure that it's always set to lower case or it won't work properly. example enlargeText and Enlargetext will always be converted to enlargetext, thus use enlarge-text instead, because its easy to read & valid, for a brief explanation about $emit you can read it here
<div id="blog-posts-events-demo">
<div :style="{ fontSize: postFontSize + 'em' }">
<blog-post
v-for="post in posts"
v-bind:key="post.id"
v-bind:post="post"
v-on:enlarge-text="onEnlargeText"></blog-post>
</div>
</div>
VUE.JS
When user clicks the button the v-on:click="$emit('enlarge-text')" will trigger then calling the function onEnlargeText() in the parent
//component (child)
Vue.component('blog-post', {
props: ['post'],
template: `
<div class="blog-post">
<h3>{{ post.title }}</h3>
<button v-on:click="$emit('enlarge-text')">
Enlarge text
</button>
<div v-html="post.content"></div>
</div>`
})
//parent
new Vue({
el: '#blog-posts-events-demo',
data: {
posts: [
{ id: 1, title: 'My journey with Vue' },
{ id: 2, title: 'Blogging with Vue' },
{ id: 3, title: 'Why Vue is so fun' }
],
postFontSize: 1
},
methods:{
onEnlargeText:function(){
this.postFontSize++;
}
}
})

Actually props suck sometimes you got some old external library in jquyer and need just damn pass value. in 99% of time use props that do job but.
A) spend tons of hours debuging changing tones of code to pass variables
B) one line solution
Create main variable in data letmeknow as object {}
this.$root.letmeknow
then somewhere in code from component
this.$root.letmeknow = this;
and then boom i got component console.log( this.$root.letmeknow ) and see now can change some values

How to keep data in component when using v-with in Vue js

So here is my problem:
I want to make a component that takes it's values from v-with="values" and add them to my component model after some modification, then display those modified properties.
But from what I understand, when I set values with "v-with", component data are erased so the binding between my component data (not v-with one) and my directives are lost.
I'm really new to this framework, I don't see any solution, so I guess it was time to ask my first question here !
Here is the HTML:
<script type="text/x-template" id="my-template">
<p v-on="click:reloadParentMsg">Msg parent : {{ParentMsg}}</p>
<p v-on="click:reloadChildMsg">Msg child : {{ChildMsg}}</p>
</script>
<div id="myVue">
<my-component v-with="ParentData" ></my-component>
</div>
And here is the Javascript:
Vue.component('my-component', {
template: '#my-template',
data: function () {
return {
ChildMsg: "wololo"
}
},
methods:{
reloadParentMsg : function(){
this.ParentMsg="Parent";
console.log(this.ParentMsg);
},
reloadChildMsg : function(){
this.ChildMsg="Child";
console.log(this.ChildMsg);
}
}
})
var myVue = new Vue({
el: '#myVue',
data: {
ParentData:{ParentMsg: "gloubiboulga"}
}
})
And the js fiddle http://jsfiddle.net/KwakawK/hfj1tv4n/3/

I'm not totally clear on what you're trying to do, but I believe it can be solved by using the second form of v-with, which is v-with="childProp: parentProp". Rather than the parent property overriding all of the child data, this will replace only the property on the left of the colon.
So I think your code can be fixed by changing the v-with to this:
<my-component v-with="ParentMsg: ParentData.ParentMsg" ></my-component>
Here's the updated code as a snippet:
// register the grid component
Vue.component('my-component', {
template: '#my-template',
data: function () {
return {
ChildMsg: "wololo"
}
},
methods:{
reloadParentMsg : function(){
this.ParentMsg="Parent";
console.log(this.ParentMsg);
},
reloadChildMsg : function(){
this.ChildMsg="Child";
console.log(this.ChildMsg);
}
}
})
// bootstrap the demo
var myVue = new Vue({
el: '#myVue',
data: {
ParentData:{ParentMsg: "gloubiboulga"}
}
})
<script src="http://cdnjs.cloudflare.com/ajax/libs/vue/0.11.4/vue.min.js"></script>
<script type="text/x-template" id="my-template">
<p v-on="click:reloadParentMsg">Msg parent : {{ParentMsg}}</p>
<p v-on="click:reloadChildMsg">Msg child : {{ChildMsg}}</p>
</script>
<div id="myVue">
<my-component v-with="ParentMsg: ParentData.ParentMsg" ></my-component>
</div>
See the Vue guide for more information.