Vue3: How to prevent further input when value meets a certain condition - vue.js

I'm primarily a React developer but I'm dipping my toes back into Vue again.
I'm making an app which allows you to convert your running pace between minutes per km and minutes per mile. The minute and second values for each unit are set in a parent component and passed down into child input components. I would like to prevent users from entering values higher than 59 into the number inputs but the v-model functionality continues to allow users to type beyond that.
I'm probably approaching this from a React mindset, so any help would be greatly appreciated!
App.vue
<template>
<div>
<NumberInput
:id="'kmMins'"
:unit="'km'"
v-model="kmMins"
/>
</div>
</template>
<script>
import NumberInput from "./NumberInput.vue";
export default {
name: "App",
data() {
return {
kmMins: 0,
}
},
components: {
NumberInput
}
}
</script>
NumberInput.vue
<template>
<input
type="number"
placeholder="00"
:value="modelValue"
#input="$emit('update:modelValue', sanitize($event))"
/>
</template>
<script>
export default {
name: "NumberInput",
props: ['id', 'unit', 'modelValue'],
methods: {
sanitize(e) {
const { value } = e.target;
if (!Number.isNaN(value) && value < 60) {
return value;
}
return this.modelValue;
}
}
}
</script>

App.vue
<template>
<div>
<NumberInput
:id="'kmMins'"
:unit="'km'"
v-model="kmMins"
/>
</div>
</template>
<script>
import NumberInput from "./NumberInput.vue";
export default {
name: "App",
data() {
return {
kmMins: 0,
}
},
components: {
NumberInput
},
watch: {
kmMins(newValue, oldValue){
if(newValue > 59){
this.kmMins = 59
}
}
}
}
</script>
Have you considered using watch? I haven't tested it but I think this will work. If it works you can deal with it for now.

<template>
<input
type="number"
placeholder="00"
v-model= "checkNumber"
/>
</template>
<script>
export default {
name: "NumberInput",
props: ['id', 'unit', 'modelValue'],
data(){
return{
checkNumber : 0,
}
},
watch:{
checkNumber(val){
if(val<5){
$emit('update:modelValue', sanitize($event))
}else{
console.log(">>> value greater then 5" , val)
}
}
},
methods: {
sanitize(e) {
const { value } = e.target;
if (!Number.isNaN(value) && value < 60) {
return value;
}
return this.modelValue;
}
}
}
</script>
in the above code i have used watch which is like useEffect in react this will watch the variable change in every change like onChange function in react.
And if the data if greater then 5 it will send error . else data will be send back to your parent div.

Related

Passing data from child component to parent and then to another child not working on page load but works after minor potentially unrelated change

I am new to Vuejs and come across this bug which I have no idea what I have done wrong. I am not receiving any console errors. It doesn't work on initial page load but it seems to work after I comment something out (or make a minor change). It will still then continue to work if I reverse the changes I just made and put it back to the original code. But once again on a fresh page load it won't work.
The issue: I am making a to do list and on page load when I add new tasks through the input field, the list does not appear on the page like it should be. I also console log the data array for this and it shows it is getting added to the array but is not getting rendered to the page. No console errors. In my code I will comment out some other data property (there are 2 additional ones below todosList in the TodoList.vue file that are currently not being used yet) and save and then the tasks will automatically appear on the page. So I think oh ok that might be the issue so with this new minor change I decide to refresh the page to see if it works as expected. Nope it doesn't so I then uncomment out what I previously commented out and save and the list appears again. But once again if I refresh the page it doesn't work. It only seems to be if I make a change inside the data function in the TodoList.vue file.
Additional info: The data is stored in the parent todos[] (App.vue), updated/pushed to array in a child (TodoCreate.vue) and sent back to the parent using $emit. This data is then sent through to another child (TodoList.vue) using props so that it can be rendered on the page.
Wondering if there is something that is not quite right in my code which is causing this to bug out like that. I will include everything in case it is something that looks unrelated to me but could be causing it.
Here is also a link to a code sandbox where the issue can be replicated by following the instructions on the page https://codesandbox.io/s/adding-new-todo-not-working-properly-jwwex?file=/src/components/TodoList.vue
main.js
import { createApp } from 'vue'
import App from './App.vue'
createApp(App).mount('#app')
App.vue
<template>
<div :class="currentMode">
<the-header #modeToggled="updateMode($event)"></the-header>
<main>
<todo-create #addedTodos="updateTodos"></todo-create>
<todo-list :todos="todos"></todo-list>
</main>
</div>
</template>
<script>
import TheHeader from './components/TheHeader.vue';
import TodoCreate from './components/TodoCreate.vue';
import TodoList from './components/TodoList.vue';
export default {
name: 'App',
components: {
TheHeader,
TodoCreate,
TodoList,
},
data() {
return {
currentMode: {
dark_mode: true,
light_mode: false
},
todos: [],
}
},
methods: {
updateMode(mode) {
this.currentMode = mode;
},
updateTodos(data) {
this.todos = data;
console.log(this.todos);
},
toggleCompleted() {
}
},
// provide() {
// return {
// todos: this.todos,
// };
// }
}
</script>
TheHeader.vue
<template>
<h1>To-do App</h1>
<div>
<label for="toggle-mode" aria-label="Toggle light and dark mode"></label>
<input type="checkbox" id="toggle-mode" #change="toggleMode">
</div>
</template>
<script>
export default {
emits: ['modeToggled'],
data() {
return {
toggleState: false,
}
},
methods: {
toggleMode() {
this.toggleState = !this.toggleState;
this.$emit('modeToggled', this.modeClasses);
}
},
computed: {
modeClasses() {
return {
dark_mode: !this.toggleState,
light_mode: this.toggleState
}
}
}
}
</script>
TodoCreate.vue
<template>
<div>
<label for="newtodo" class="sr-only">Create new to do</label>
<input type="text" id="newtodo" placeholder="Create a new todo..." v-model="todoval" v-on:keyup.enter="addTodo" >
</div>
</template>
<script>
export default {
emits: ['addedTodos'],
data() {
return {
todoval: '',
taskNumber: 0,
todos: [],
};
},
methods: {
addTodo() {
const val = this.todoval;
const taskNumber = this.taskNumber;
this.todos.push({ taskID: taskNumber, value: val, complete : 'not-completed'});
this.todoval = '';
this.taskNumber++;
console.log(this.todos);
this.$emit('addedTodos', this.todos);
},
}
}
</script>
TodoList.vue
<template>
<ul class="todo-items" :class="filterClass">
<li class="drop-zone" v-for="(listItem, index) in todosList" :class="listItem.complete" :key="listItem.taskID"
#drop='onDrop($event, index)'
#dragover.prevent
#dragenter.prevent>
<div class="drag-el" draggable="true"
#dragstart='startDrag($event, index)'>
<label :for="'checkbox-'+index" :aria-label="'Mark task ' + listItem.value + ' as completed'"></label>
<input type="checkbox" :id="'checkbox-'+index" #change="toggleCompleted(index, listItem.value, listItem.complete, listItem.taskID)">
<input type="text" disabled :value="listItem.value">
<img src="../assets/icon-cross.svg" #click="removeTask(index)">
</div>
</li>
</ul>
</template>
<script>
export default {
props: {
todos: Object,
filterClass: String
},
// inject: ['todos'],
data() {
return {
todosList: this.todos,
// completedTodos: [],
// activeTodos: [],
};
},
// watch: {
// todosList(data) {
// data.filter(function(todo) {
// if(todo.completed == 'completed') {
// completedTodos.push(todos);
// }
// });
// }
// },
methods: {
startDrag: (evt, item) => {
evt.dataTransfer.dropEffect = 'move'
evt.dataTransfer.effectAllowed = 'move'
evt.dataTransfer.setData('itemID', item)
},
onDrop (evt, list) {
const itemID = evt.dataTransfer.getData('itemID');
const movedData = this.todosList[itemID];
this.todosList.splice(itemID,1);
this.todosList.splice(list,0, movedData);
},
toggleCompleted() {
// still need to write this method
},
removeTask() {
// still need to write this method
}
}
}
</script>

How to make a function from another brother component be called when pressed?

Good afternoon, tell me please, I wrote a calendar displaying the events that the user sets, and now I want to make a detailed display of the event when I click it. The problem is that the events are in my component and the whole display logic is in another, how can I use them together.I want to make it so that the getDetailInformation() function in the ModalWindowDetail component component is called by clicking on an event in another component Calendar.vue. I use the event bus, but nothing works for me, I don’t understand why. Please help me solve this problem.
Screenshot of Calendar and error in console
Code of Calendar on GitHub
App.vue:
<template>
<div class="all">
<app-calendar #sendTextEvent="text = $event"></app-calendar>
<app-detail v-if="modalWindowDetail"
:eventText="text"></app-detail>
</div>
</template>
<script>
import appCalendar from './components/Calendar.vue'
import appDetail from './components/ModalWindowDetail.vue'
export default {
data(){
return{
text: String
}
},
components: {
appCalendar,
appDetail
},
computed: {
modalWindowDetail() {
return this.$store.state.modalWindowDetail;
}
}
};
</script>
Calendar.vue component which display calendar:
<template>
<div class="overflow-div">
<transition :name="nameOfClass" >
<div :key="currentPage" class="fade_wrapper">
<div v-for="(week, i) in getCalendar" class="d_day">
<li v-for="day in week" class="li_day">
<div class="day">{{ day }}</div>
<div v-for="event in buildEvents(i, day)"
class="event"
v-bind:class="{ 'eventBrown': eventBrown(event),
'eventPurple': eventPurple(event),
'eventOrange': eventOrange(event),
'eventBlue': eventBlue(event) }"
v-on:click="openModalDetail(event)">{{ event }}
</div>
</li>
</div>
</div>
</transition>
</div>
</template>
<script>
import json from './Calendar_data.json'
import { mapState } from "vuex";
import { eventBus } from './../main.js'
export default {
mounted(){
eventBus.$on('getDetailInformation', this.openModalDetail())
},
computed: {
modalWindowDetail() {
return this.$store.state.modalWindowDetail;
},
},
methods: {
openModalDetail(text){
this.$emit('sendTextEvent', text);
}
};
</script>
The component in which the getDetailInformation() is located ModalWindowDetail.vue:
<template>
<div class="underModalWindow">
<div class="modalWindow">
<img src="src/assets/x.png" width="20px" height="20px">
<div class="nameofModal">Вся детальная информация о событии</div>
<div v-for="(key, name) in eventDetail" class="detailEvent">{{ name }}: {{ key }}</div>
<button>Окей</button>
</div>
</div>
</template>
<script>
import { eventBus } from './../main.js'
export default {
props: ['eventText'],
data(){
return{
options: [
{ text: 'Встреча', value: '8' },
{ text: 'День Рождения', value: '4' },
{ text: 'Праздник', value: '1' },
{ text: 'Другое', value: '16' }
],
eventDetail: Object,
}
},
computed: {
eventsData() {
return this.$store.state.eventData;
},
modalWindowDetail() {
return this.$store.state.modalWindowDetail;
},
},
created(){
eventBus.$emit('getDetailInformation', this.getDetailInformation())
},
methods: {
getDetailInformation(){
let arrOfEvents = this.eventsData.events;
for(let z = 0; z < arrOfEvents.length; z++){
let memo = arrOfEvents[z].memo;
console.log(this.memo)
if(memo === this.eventText){
let dataStartOfEvent = arrOfEvents[z].starts_at;
let getStartDataOfEvent = new Date(dataStartOfEvent);
let dataEndOfEvent = arrOfEvents[z].ends_at;
let getEndDataOfEvent = new Date(dataEndOfEvent);
if((getStartDataOfEvent.getHours() - 3) > 0){
this.$store.commit('changeModalWindowDetail', this.modalWindowDetail);
this.eventDetail = {
'Событие': this.eventText,
'Начало события': getStartDataOfEvent.toLocaleTimeString(),
'Конец события': getEndDataOfEvent.toLocaleTimeString(),
'Тип события': this.getType(arrOfEvents[z].type)
}
}else if(getStartDataOfEvent.getDate() != getEndDataOfEvent.getDate()){
this.$store.commit('changeModalWindowDetail', this.modalWindowDetail);
this.eventDetail = {
'Событие': this.eventText,
'Начало события': getStartDataOfEvent.toLocaleDateString(),
'Конец события': getEndDataOfEvent.toLocaleDateString(),
'Тип События': this.getType(arrOfEvents[z].type)
}
}
}
}
}
}
};
</script>
You should remove the () from the function name in eventBus.$on('getDetailInformation', this.openModalDetail()) - you want to reference the function, not to call it and use the result as a reference.
Also, your function getDetailInformation() does not return anything - but you seem to expect that it returns a text. You should correct this.
And finally, I think that #sendTextEvent="text = arguments[0]" would be more appropriate - and using a dedicated method/function will be the best.

How to update data from vue-tables-2 after action from Template?

I'm using a custom component as a column on vue-tables-2, to do that I'm using a vue-component as described here: vue-components
I've created a button that opens a modal to the user confirm some information, and after that I make a request to the backend and the record is changed on the database.
Now I want to refresh the data on the table, but I don't know how to do that. The documentation said about using the $ref, but this is not an option because my component is not the parent.
How can I do that?
Links to the code:
Component using 'vue-tables-2'
<template>
<div>
<div id="payment">
<input type="checkbox" v-model="onlyPending" #change="filterPay()">Apenas pendentes</input>
<v-server-table url="/api/payments" :columns="columns" :options="options" ></v-server-table>
</div>
</div>
</template>
<script>
import pay from './ModalConfirmPay.vue'
import {Event} from 'vue-tables-2';
export default {
name: "AeraListPayment",
props: ['groupId'],
data: function(){
let groupId = this.groupId;
return {
columns: ['name','value','course','due_date','paid','installment','pay'],
options: {
responseAdapter : function(data) {
data.data = data.data.map(payment => {
payment.paid = payment.paid ? "pago" : "pendente";
return payment;
})
return data;
},
headings: {
installment: 'Parcela',
paid: 'Status',
value: 'Valor',
due_date: 'Vencimento',
pay: 'Ação',
course: 'Curso',
name: 'Nome'
},
templates : {
pay
},
customFilters: ['onlyPending','groupId'],
initFilters:{groupId:groupId,onlyPending:true}
},
onlyPending: true
}
},
methods: {
filterPay(){
Event.$emit('vue-tables.filter::onlyPending', this.onlyPending);
}
}
}
</script>
Component that is being used as a custom column:
<template>
<div>
<button #click.prevent="show">Pagar</button>
<modal :name="modalName">
<p>Confirma o pagamento de {{data.value}} ?</p>
<p>Parcela: {{data.installment}}</p>
<p>Vecimento: {{data.due_date}}</p>
<button #click.prevent="pay">Confirmar</button>
<button #click.prevent="hide">Cancelar</button>
</modal>
</div>
</template>
<script>
import PaymentService from '../../services/PaymentService'
let service = new PaymentService();
export default {
name:"ModalConfirmPay",
props: ["data"],
computed: {
modalName: function () {
// `this` aponta para a instância Vue da variável `vm`
return `confirm-pay-${this.data.clientGroup_id}-${this.data.installment}`
}
},
methods: {
show () {
this.$modal.show(this.modalName);
},
pay ( ) {
service.pay(this.data)
.then(this.hide());
},
hide () {
this.$modal.hide(this.modalName);
}
}
}
</script>
First, defined an EventBus if you don't have
EventBus.vue
import Vue from 'vue'
export default new Vue()
In ListPayment.vue, import EventBus and listen for refresh-table event. Note that I add ref="table" to vue-tables-2 element
<template>
<v-server-table ref="table" ... />
</template>
<script>
import EventBus from './EventBus.vue'
export default {
mounted() {
EventBus.$on('refresh-table', this.refreshTable)
},
beforeDestroy() {
EventBus.$off('refresh-table', this.refreshTable)
},
methods: {
refreshTable() {
this.$refs.table.refresh();
}
}
}
</script>
Finally, emit event in modal
pay() {
service.pay(this.data)
.then(() => {
EventBus.$emit('refresh-table')
})
.then(this.hide());
}

How to pass and change index of array in vue?

I have the gist of how to do this, but I'm a beginner in vue, and I'm struggling with how to put it together. I need Control.vue to update the index in Exhibitor.vue. I know I'll have an $emit event happening in Control when I click on the button to pass the index data to the parent, and I'd have to use props to pass data from Exhibitor to its children, but how? I can't understand how to pass the index of an array with my code.
Exhibitor.vue
<template>
<div id="exhibitor">
<section class="exhibitor_info">
<h1 class="exhibitor_name">{{ exhibitors[index].firstName }} {{ exhibitors[index].lastName }}</h1>
<h2>Tag Number: {{ exhibitors[index].tagNum }} <em>{{ exhibitors[index].species }}</em></h2>
</section>
<div class="frame"><img :src="getImgUrl(exhibitors[index].picture)" alt="Exhibitor-Picture" class="image"></div>
</div>
</template>
<script>
export default {
name: 'Exhibitor',
data() {
return {
exhibitors: [],
index: 0
}
},
created: function() {
this.fetchExhibitors();
},
methods: {
fetchExhibitors() {
let uri = 'http://localhost:8081/exhibitor'
this.axios.get(uri).then(response => {
this.exhibitors = response.data
})
},
getImgUrl: function(pic) {
return require('../assets/' + pic)
}
}
}
</script>
Display.vue
<template>
<div id="display">
<exhibitor></exhibitor>
<buyer></buyer>
</div>
</template>
<script>
import Exhibitor from './Exhibitor.vue';
import Buyer from './Buyer.vue';
export default {
components: {
'exhibitor': Exhibitor,
'buyer': Buyer
}
}
</script>
Control.vue
<template>
<div id="control">
<display></display>
<button v-on:click="incrementLeft">Left</button>
<button v-on:click="incrementRight">Right</button>
</div>
</template>
<script>
import Exhibitor from './Exhibitor.vue';
import Display from './Display.vue';
export default{
props: ['exhibitors', 'buyers', 'index'],
data() {
return {
index: 0
}
},
methods: {
incrementRight: function() {
// Note that '%' operator in JS is remainder and NOT modulo
this.index = ++this.index % this.exhibitors.length
},
incrementLeft: function() {
// Note that '%' operator in JS is remainder and NOT modulo
if (this.index === 0) {
this.index = this.exhibitors.length - 1
} else {
this.index = --this.index % this.exhibitors.length
}
}
},
components: {
'display': Display
}
}
</script>
So you can get what you want to happen and there are two ways of making it happen that I can think of. First I will just clarify the terms relating to this because you seem to have them the wrong way around. Let's look at you tier structure which is like this:
Control.vue
contains: Display.vue
contains: Exhibitors.vue & Buyers.vue.
Therefore Control.vue is the parent of Display.vue which is the parent of Buyers.vue and Exhibitors.vue.
Anyway, What we need to do is control the array of exhibitors (and I guess buyers but you didn't include them in your code so I'll do likewise) which is in Exhibitors.vue from Control.Vue even though they don't have a direct parent child relationship. What I've done is set a prop that is passed to Display.vue which uses scoped slots to render the exhibitors from Exhibitors.Vue. Because the left and right buttons need to know when to stop going I have emitted the array length from Exhibitors.vue to Display.vue and again to Control.vue. It all works so heres some code.
//Control.vue
<template>
<div class="content">
<display v-on:finalLength="setIndexLimit" :i="index"></display>
<button #click="changeDown">Down</button>
<button #click="changeUp">Up</button>
<p>{{indLimit}}</p>
</div>
</template>
<script>
import Display from '#/components/Display'
export default {
components: {
Display
},
data: () => ({
index: 0,
indLimit: 0
}),
methods: {
changeUp() {
if (this.indLimit === this.index+1) {
this.index=0
}
else {
this.index ++
}
},
changeDown() {
if (this.index === 0) {
this.index = this.indLimit - 1
}
else {
this.index --
}
},
setIndexLimit(e) {
this.indLimit = e
}
}
}
</script>
and
//Display.vue
<template>
<div id="display">
<p>From Display</p>
<exhibitors v-on:ExLength="setLength">
<p>{{i}}</p>
</exhibitors>
<exhibitors>
<p slot-scope="{ exhibitors }">{{exhibitors[i].firstName}}</p>
</exhibitors>
<exhibitors>
<p slot-scope="{ exhibitors }">{{exhibitors[i].lastName}}</p>
</exhibitors>
<exhibitors>
<p slot-scope="{ exhibitors }">{{exhibitors[i].tagNum}}</p>
</exhibitors>
<exhibitors>
<p slot-scope="{ exhibitors }">{{exhibitors[i].species}}</p>
</exhibitors>
</div>
</template>
<script>
import Child from '#/components/admin/Exhibitors'
export default {
components: {
Exhibitors
},
props: [
'i'
],
data: () => ({
exhibitLength: null
}),
methods: {
setLength(e) {
this.exhibitLength = e
this.$emit('finalLength',e)
}
}
}
</script>
And finally:
//Exhibitors.vue
<template>
<div>
<slot :exhibitors="exhibitors"><p>I'm the child component!</p></slot>
</div>
</template>
<script>
export default {
data: () => ({
exhibitors: [
{
firstName: 'Joe',
lastName: 'Burns',
tagNum: 1,
species: 'ant'
},
{
firstName: 'Tom',
lastName: 'Yorke',
tagNum: 2,
species: 'bee'
},
{
firstName: 'Flit',
lastName: 'Argmeno',
tagNum: 3,
species: 'giraffe'
}
],
}),
mounted: function () {
this.$nextTick(function () {
let length = this.exhibitors.length
this.$emit('ExLength', length)
})
}
}
</script>
So as I said all that works, you can click the buttons and it will loop through the array contents. You can style it how you want wherever you like. However, it is a bit messy with props and slots and emits and whatnot just to relay a single index number and it would be far easier in my opinion to have a vuex store where 'index' is stored as a state item and can be used and changed anywhere without all the above carry on.

Vue component data not updating from props

I'm building a SPA with a scroll navigation being populated with menu items based on section components.
In my Home.vue I'm importing the scrollNav and the sections like this:
<template>
<div class="front-page">
<scroll-nav v-if="scrollNavShown" #select="changeSection" :active-section="activeItem" :items="sections"></scroll-nav>
<fp-sections #loaded="buildNav" :active="activeItem"></fp-sections>
</div>
</template>
<script>
import scrollNav from '.././components/scrollNav.vue'
import fpSections from './fpSections.vue'
export default {
data() {
return {
scrollNavShown: true,
activeItem: 'sectionOne',
scrollPosition: 0,
sections: []
}
},
methods: {
buildNav(sections) {
this.sections = sections;
console.log(this.sections)
},
changeSection(e) {
this.activeItem = e
},
},
components: {
scrollNav,
fpSections
}
}
</script>
this.sections is initially empty, since I'm populating this array with data from the individual sections in fpSections.vue:
<template>
<div class="fp-sections">
<keep-alive>
<transition
#enter="enter"
#leave="leave"
:css="false"
>
<component :is="activeSection"></component>
</transition>
</keep-alive>
</div>
</template>
<script>
import sectionOne from './sections/sectionOne.vue'
import sectionTwo from './sections/sectionTwo.vue'
import sectionThree from './sections/sectionThree.vue'
export default {
components: {
sectionOne,
sectionTwo,
sectionThree
},
props: {
active: String
},
data() {
return {
activeSection: this.active,
sections: []
}
},
mounted() {
this.buildNav();
},
methods: {
buildNav() {
let _components = this.$options.components;
for(let prop in _components) {
if(!_components[prop].hasOwnProperty('data')) continue;
this.sections.push({
title: _components[prop].data().title,
name: _components[prop].data().name
})
}
this.$emit('loaded', this.sections)
},
enter(el) {
twm.to(el, .2, {
autoAlpha : 1
})
},
leave(el, done) {
twm.to(el, .2, {
autoAlpha : 0
})
}
}
}
</script>
The buildNav method loops through the individual components' data and pushes it to a scoped this.sections array which are then emitted back to Home.vue
Back in Home.vue this.sections is populated with the data emitted from fpSections.vue and passed back to it as a prop.
When I inspect with Vue devtools the props are passed down correctly but the data does not update.
What am I missing here? The data should react to props when it is updated in the parent right?
:active="activeItem"
this is calld "dynamic prop" not dynamic data. You set in once "onInit".
For reactivity you can do
computed:{
activeSection(){ return this.active;}
}
or
watch: {
active(){
//do something
}
}
You could use the .sync modifier and then you need to emit the update, see my example on how it would work:
Vue.component('button-counter', {
template: '<button v-on:click="counter += 1">{{ counter }}</button>',
props: ['counter'],
watch: {
counter: function(){
this.$emit('update:counter',this.counter)
}
},
})
new Vue({
el: '#counter-sync-example',
data: {
foo: 0,
bar: 0
}
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.2/vue.min.js"></script>
<div id="counter-sync-example">
<p>foo {{ foo }} <button-counter :counter="foo"></button-counter> (no sync)</p>
<p>bar {{ bar }} <button-counter :counter.sync="bar"></button-counter> (.sync)</p>
</div>