I do have three components.
I don't have any influence on what the Datatable component does cause I have it from npm.
Now I want to send an event from EditButton to my Zonelist.
Zonelist component:
<template>
<datatable :columns="table_columns" :data="table_rows" filterable paginate v-on:remove="removeItem"></datatable>
</template>
<script>
import datatable from 'vuejs-datatable';
import moment from 'moment';
export default {
data() {
return {
table_columns: [
{label: "Zone", component: 'ZoneLink'},
{label: "Last updated", callback (row) {
let locale = $('html').closest('[lang]').attr('lang') || 'en';
moment.locale(locale);
return moment(row.last_updated).format('D. MMM YYYY');
}},
{label: '', component: 'EditButton'}
],
table_rows: [
{
"name": "xyz.de",
"last_updated": "2017-10-21 17:29:50"
}
],
form: {
name: '',
errors: []
}
};
},
components: {
datatable
},
methods: {
removeItem (item) {
this.table_rows.forEach((value, index, array) => {
if (value.name === item) {
Vue.delete(array, index);
}
});
}
}
}
</script>
Now my EditButton component $emit()'s the remove event with a parameter.
But nothing happens. So I think vue is not able to locate the listener.
(I'm using method shorthands from ES6 here)
How could I do this properly without mutating Zonelist's state via this.$parent.$parent from the EditButton?
Non parent-child communication in Vue is typically handled via either an event bus, or a state management system.
In this case, unless your application is more complex, the event bus is probably all you need. Since you are using single file components, you may need to declare the bus on the window, probably in your main script.
window.bus = new Vue()
Then in your EditButton, you can emit the event
bus.$emit('some-event', someData)
And in your ZoneList you can listen for it.
bus.$on('some-event', someData => this.doSomething(someData))
Another option is to ask DataTable to pass any and all events up by adding a v:on="$listeners" attribute to it.
See https://stackoverflow.com/a/61329264/578318 for a more detailed explanation.
Edit:
A much safer option would be to simply listen to the event in the parent class and pass it on...
<ancestor #message="console.log($event)"> <!-- cute trick see * -->
...
<parent #message="$emit('message', $event)"> <!-- passes it on -->
...
<child #click="$emit('Hello World')"> <!-- creates the event -->
* computed: {'console' : () => console}
By default, if a Vue component only has one node in it (i.e. no child nodes), then all events that you attach to it from the parent will fire just like if it were a regular HTML element.
But what if you have a child node that has children? In that case, you want to use v-on="$listeners"
Example:
<template>
<div v-on="$listeners">
<button>Hello world</button>
</div>
</template>
Docs: https://v2.vuejs.org/v2/guide/components-custom-events.html#Binding-Native-Events-to-Components
Related
I am having a rather strange problem with vue (v2.6.14) in which I am creating a new array based on one receive as a prop. Here's the relevant code:
props: { employees: Array },
data() {
return {
sortedEmployees: [],
};
},
mounted() {
this.sortedEmployees = this.employees.slice(0);
},
Essencially what I want here is to create a new reference for the employees array so that I can sort it to display later without actually altering the original array. I am not worried about cloning the actual objects inside the array since I will not alter them.
The problem with this is that, when the app 'hot reloads'(due to some change in the code) it works as expected, the hook is called and the component data is set according to what is expected BUT if I actually refresh the page in the browser, even though the hook is called, the component data is not set and I end up with an empty array. I can solve this by setting up a watcher to the prop and then it would set the data there, but what I am interested here is understanding what's happening. If the hook is called when the page is refreshed why doesn't it set the data properly as it does when 'hot reloading'?
I have a minimal setup created with vue-cli, no fancy configurations whatsoever. Any clue what I might be missing?
I guess the employees are loaded async, right?
I don't know your exact application structure, but the problem is usually the following:
The mounted hook gets called, when the component mounts, of course. If the employees are loaded async in the parent component, the mount hook is called, before the async call is resolved. So it will copy an empty array at this time.
With a watcher you solve this problem, because the watcher fires as soon as the async call resolves (as it mutates the employees array).
Same happens to the hotreload. When the hotreload occurs, the mounted hook gets executed again - at this time the employees array is already prefilled with values and therefore the correct array is copied in the mount hook.
Update
If you want to avoid watchers, you could also wrap your component like this:
<your-component
v-if="employees.length > 0"
:employees="employees"
/>
Be aware, that the copied employees array IN your component is still not reactive. It just copies the array on the first time it has more than 1 value. A watcher really makes sense in this case.
If you use watchers, make sure to use the immediate: true option. This ensures, that the watcher is also called the first time on render (and also on hotreload).
Summary
If you really want to copy the array, use watchers (with the immediate: true flag).
If it's just about sorting, go for the computed property solution suggested by #Sebastian Scholl
It sounds like the component is Refreshing (reseting) with the prop change however it's not Re-mounting. This is what would cause the array to reset to it's default state ([]), whereas on hot-reload the actual page is reloading.
Try the following, and if it doesn't resolver the issue I would suggest going the route of using a Watcher.
<template>
<div>
sorted: {{ sortedEmployees }}
<br />
not sorted: {{ employees }}
</div>
</template>
<script>
export default {
props: {
employees: Array,
},
data() {
return {
sortedEmployees: Array.from(this.employees),
};
}
};
</script>
Another approach is to just use a Computed method so and add any filtering/sorting logic inside that method. It would be something like:
<template>
<div>
<input v-model="sortKey" />
sorted: {{ sortedEmployees }}
</div>
</template>
<script>
export default {
props: {
employees: Array,
},
data () {
return {
sortKey: ''
}
},
computed: {
sortedEmployees() {
return Array.from(this.employees).sort(this.sortingFunction);
},
},
methods: {
sortingFunction(a, b) {
// sorting function using this.sortKey
}
}
};
</script>
UPDATED ANSWER
I switched up the code in the example a little and believe to have gotten it to work as I you're describing.
App.js
First off, I made it so that the employees array is updated after 3 seconds.
<template>
<div id="app">
<Dashboard :employees="employees" />
</div>
</template>
<script>
import Dashboard from './components/Dashboard.vue';
export default {
name: 'App',
components: { Dashboard },
data () {
return {
employees: [
{
employeeId: '1',
firstName: 'Leite',
}
]
};
},
methods: {
updateEmployees () {
this.employees = this.employees.concat([
{
employeeId: '2',
firstName: 'Jacinto',
},
{
employeeId: '3',
firstName: 'Capelo',
}
]);
}
},
mounted () {
setTimeout(this.updateEmployees, 3000)
},
};
</script>
Dashboard.js
The updated() lifecycle hook runs whenever data changes are detected (props and data properties). This effectively detected the change in the prop passed by the parent App.js component and re-rendered the data - whereas the mounted hook only ran once per page load.
<template>
<div id="dashbord">
<div
v-for="(employee, index) in sortedEmployees"
:key="employee.employeeId"
>
{{ employee.firstName }}
</div>
</div>
</template>
<script>
export default {
name: 'Dashboard',
props: {
employees: Array
},
data() {
return {
sortedEmployees: Array.from(this.employees)
};
},
updated() {
this.sortedEmployees = Array.from(this.employees)
}
};
</script>
could it be that Inertia.js page components are blocking the reactivity of vue?
I have a Page component, in this component is a normal single file component.
I have a function that adds items to the ItemsManager.items object.
When I'm running this function the single component below doesnt adds this items in the v-for.
But when I'm reload the Page Component it works and the previously added items appear.
Here the single file component:
<template>
<div>
<div v-for="item in items" :key="item.$key">
test
</div>
</div>
</template>
<script>
import { ItemsManager } from "./utils.js";
export default {
name: "test-component",
data: () => ({
items: ItemsManager.items
}),
};
</script>
utils.js:
export const ItemsManager = {
items: [],
add(item) {
item.$key = this.items.length;
this.items.unshift(item);
},
};
function that adds the items (in page component):
addItem(title, options) {
ItemsManager.add({
name: title,
options: options
});
},
Thanks in advance!
Since you're using Vue2, you need to know that there are some caveats when adding/deleting things to Objects/Arrays. You don't show any code relevant to your actual way of adding stuff to your object, but I can still recommend that you'd check this page to understand and fix your issue.
https://v2.vuejs.org/v2/guide/reactivity.html#Change-Detection-Caveats
I have a list of instruments that should render a c-input with autosuggest window when the user types something. Also, I need an option for c-input to add or remove autosuggest component.
/* instrument component */
<template>
<c-input ref="input"
:values="inputValue"
:placeholder="placeholder"
#input="onInput"
#change="onChangeInput"
#reset="reset" />
<autosuggest
v-if="showSuggests"
:inputValue="inputValue"
:suggests="suggests"
#onSelectRic="selectRicFromList"
></autosuggest>
</div>
</template>
<script>
export default {
name: 'instrument',
data: () => ({
suggests: [],
inputValue: '',
}),
computed: {
showSuggests() {
return this.isNeedAutosuggest && this.showList;
},
showList() {
return this.$store.state.autosuggest.show;
},
isloading() {
return this.$store.state.instruments.showLoading;
},
defaultValue() {
if (this.instrument.name) {
return this.instrument.name;
}
return '';
},
},
[...]
};
</script>
This is a parent component:
<template>
<div>
<instrument v-for="(instrument, index) in instruments"
:key="instrument.name"
:instrument="instrument"
:placeholder="$t('change_instrument')"
:isNeedAutosuggest="true" /> <!--that flag should manage an autosuggest option-->
<instrument v-if="instruments.length < maxInstruments"
ref="newInstrument"
:isNeedAutosuggest="true" <!-- here too -->
:placeholder="$t('instrument-panel.ADD_INSTRUMENT')" />
</div>
</template>
The main issues are I have so many autosuggests in DOM as I have instruments. In other words, there is should be 1 autosuggest component when the option is true. Moving autosuggest to the parent level is not good because of flexibility and a lot of logically connected with c-input.
Have you any ideas to do it?
[UPDATE]
Here is how I've solve this;
I created an another component that wraps input and autosuggest components. If I need need an input with autosuggest I will use this one, either I will use a simple input.
/* wrapper.vue - inserted into the Instrument.vue*/
<template>
<span>
<fc-input ref="input"
:values="value"
:placeholder="placeholder"
:isloading="isloading"
#input="onInput"
#changeInput="$emit('change', $event)"
#resetInput="onResetInput" />
<fc-autosuggest
v-if="isSuggestsExist"
:suggests="suggests"
/>
</span>
</template>
You can do it if you create a function inside each instrument component, which will call the parent component and search the first component instrument to find autosuggest. Function will be like that:
name: 'instrument',
...
computed: {
autosuggestComponent () {
// this is a pseudo code
const parentChildrenComponents = this.$parent.children();
const firstChild = parentChildrenComponents[0];
const autosuggestEl = firstChild.$el.getElementsByTagName('autosuggest')[0];
// return Vue component
return autosuggestEl.__vue__;
}
},
methods: {
useAutosuggestComponent () {
this.autosuggestComponent.inputValue = this.inputValue;
this.autosuggestComponent.suggests = [{...}];
}
}
This solution is not so beautiful, but it allows to keep the logic inside the instrument component.
But my advice is create some parent component which will contain instrument components and I suggest to work with autosuggest through the parent. You can create autosuggest component in the parent and pass it to the children instruments. And if instrument doesn't receive a link to a autosuggest (in props), than it will create autosuggest inside itself. It will allow to use instrument for different conditions.
Let me know if I need to explain my idea carefully.
I'm using Vue v1.0.28 and vue-resource to call my API and get the resource data. So I have a parent component, called Role, which has a child InputOptions. It has a foreach that iterates over the roles.
The big picture of all this is a list of items that can be selected, so the API can return items that are selected beforehand because the user saved/selected them time ago. The point is I can't fill selectedOptions of InputOptions. How could I get that information from parent component? Is that the way to do it, right?
I pasted here a chunk of my code, to try to show better picture of my problem:
role.vue
<template>
<div class="option-blocks">
<input-options
:options="roles"
:selected-options="selected"
:label-key-name.once="'name'"
:on-update="onUpdate"
v-ref:input-options
></input-options>
</div>
</template>
<script type="text/babel">
import InputOptions from 'components/input-options/default'
import Titles from 'steps/titles'
export default {
title: Titles.role,
components: { InputOptions },
methods: {
onUpdate(newSelectedOptions, oldSelectedOptions) {
this.selected = newSelectedOptions
}
},
data() {
return {
roles: [],
selected: [],
}
},
ready() {
this.$http.get('/ajax/roles').then((response) => {
this.roles = response.body
this.selected = this.roles.filter(role => role.checked)
})
}
}
</script>
InputOptions
<template>
<ul class="option-blocks centered">
<li class="option-block" :class="{ active: isSelected(option) }" v-for="option in options" #click="toggleSelect(option)">
<label>{{ option[labelKeyName] }}</label>
</li>
</ul>
</template>
<script type="text/babel">
import Props from 'components/input-options/mixins/props'
export default {
mixins: [ Props ],
computed: {
isSingleSelection() {
return 1 === this.max
}
},
methods: {
toggleSelect(option) {
//...
},
isSelected(option) {
return this.selectedOptions.includes(option)
}
},
data() {
return {}
},
ready() {
// I can't figure out how to do it
// I guess it's here where I need to get that information,
// resolved in a promise of the parent component
this.$watch('selectedOptions', this.onUpdate)
}
}
</script>
Props
export default {
props: {
options: {
required: true
},
labelKeyName: {
required: true
},
max: {},
min: {},
onUpdate: {
required: true
},
noneOptionLabel: {},
selectedOptions: {
type: Array
default: () => []
}
}
}
EDIT
I'm now getting this warning in the console:
[Vue warn]: Data field "selectedOptions" is already defined as a prop. To provide default value for a prop, use the "default" prop option; if you want to pass prop values to an instantiation call, use the "propsData" option. (found in component: <default-input-options>)
Are you using Vue.js version 2.0.3? If so, there is no ready function as specified in http://vuejs.org/api. You can do it in created hook of the component as follows:
// InputOptions component
// ...
data: function() {
return {
selectedOptions: []
}
},
created: function() {
this.$watch('selectedOptions', this.onUpdate)
}
In your InputOptions component, you have the following code:
this.$watch('selectedOptions', this.onUpdate)
But I am unable to see a onUpdate function defined in methods. Instead, it is defined in the parent component role. Can you insert a console.log("selectedOptions updated") to check if it is getting called as per your expectation? I think Vue.js expects methods to be present in the same component.
Alternatively in the above case, I think you are allowed to do this.$parent.onUpdate inside this.$watch(...) - something I have not tried but might work for you.
EDIT: some more thoughts
You may have few more issues - you are trying to observe an array - selectedOptions which is a risky strategy. Arrays don't change - they are like containers for list of objects. But the individual objects inside will change. Therefore your $watch might not trigger for selectedOptions.
Based on my experience with Vue.js till now, I have observed that array changes are registered when you add or delete an item, but not when you change a single object - something you need to verify on your own.
To work around this behaviour, you may have separate component (input-one-option) for each of your input options, in which it is easier to observe changes.
Finally, I found the bug. I wasn't binding the prop as kebab-case
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();