Tried EventEmitter but no chance and so little documentation... Any help appreciated
I have a component called sidebar and another one called header, when you click on a button from the header, it should hide the sidebar... How would you achieve this in angular2 ?
thanks
This is pretty easy with a Service you share between your Components.
For instance a SidebarService:
#Injectable()
export class SidebarService {
showSidebar: boolean = true;
toggleSidebar() {
this.showSidebar = !this.showSidebar;
}
}
In your sidebar component just put a *ngIf with the showSidebar variable from the SidebarService. Also don't forget to add the service in the constructor.
#Component({
selector: 'sidebar',
template: `
<div *ngIf="_sidebarService.showSidebar">This is the sidebar</div>
`,
directives: []
})
export class SidebarComponent {
constructor(private _sidebarService: SidebarService) {
}
}
In the component, where you want to handle the toggling of the sidebar also inject the SidebarService and add the click event with the service method.
#Component({
selector: 'my-app',
template: `
<div>
<button (click)="_sidebarService.toggleSidebar()">Toggle Sidebar</button>
<sidebar></sidebar>
</div>
`,
directives: [SidebarComponent]
})
export class App {
constructor(private _sidebarService: SidebarService) {
}
}
Don't forget to add the SidebarService to the providers in your bootstrap:
bootstrap(App, [SidebarService])
Plunker for example usage
Related
In vue is possible to bind button click directly from vue instance?
I have this button:
<el-button #click="alert_me" class="gf-button" type="primary" style="margin-left: 16px;">Button</el-button>
I wan't to remove #click="alert_me" and do like i would normally do with jquery but with vue.
Is it possible?
My Vue Instance:
new Vue({
el: "#app",
data: {
},
methods: {
alert_me() {
alert('Hello from vue!');
}
},
});
Thanks
If you need to attach a click event listener programmatically, it is possible with the classic javascript api:
<template>
<el-button class="gf-button" type="primary">Button</el-button>
</template>
<script>
export default {
mounted () {
// jquery would also work if it's installed.
document.getElementByClassName('gf-button').addEventListener('click', this.alert_me)
},
methods: {
alert_me() {
console.log('alert')
}
}
}
</script>
You could avoid the manual element query from the document with the Vue $refs object.
<template>
<el-button ref="myButton" class="gf-button" type="primary">Button</el-button>
</template>
<script>
export default {
mounted () {
this.$refs.myButton.addEventListener('click', this.alert_me)
},
methods: {
alert_me() {
console.log('alert')
}
}
}
</script>
But if you need that event as soon as the Vue component is created, I wouldn't recommend doing this. It kinda oversee the shadow dom optimisation of Vue.
The #click="" syntax provided is the best way to attach a click listener to an html element.
You can make use of addEventListener and call it in mounted life cycle.
mounted() {
document.querySelector('#element').addEventListener('click', event =>
{
//handle click
}
)
}
I have a component for a LineChart, here is the code :
<script>
import { Line } from 'vue-chartjs'
export default {
extends: Line,
props: ['data', 'options'],
mounted () {
this.renderChart(this.data, this.options)
}
}
</script>
I want to use this component in another one as I can affect data to data and options value of the component Chart.vue.
I'm new to VueJS and can't understand an example like that in vue-chartjs doc.
Here is my component that will be the parent one, and what I've done from now :
<template>
<div class="dashboard">
<chart></chart>
</div>
</template>
<script>
import Chart from '#/components/Chart'
export default {
name: 'DashBoard',
components: {
'chart': Chart
},
mounted () {},
data () {
return {
datacollection: null
}
}
}
</script>
<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
</style>
Where does your data come from?
Your example code is weird, as you are not passing your data as props.
So no wonder, that nothing shows up.
You have to pass your datacollection to your chart component.
<chart :data="datacollection" />
And keep in mind, that if you are using an API your data will arrive async. So the component mounts, renders the chart but your data is not there. So you need to add a v-if to be sure that your api call is finished.
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();
Trying to learn vuejs I got to the question how to pass any data from one component to all, using $emit but without using any #click.
It is possible some how that the data to be just available and grab it any time, without using the click?
Let's say we have this example with normal #click and $emit.
main.js
export const eventBus = new Vue()
Hello.vue
<template>
<div>
<h2>This is Hello component</h2>
<button
#click="emitGlobalClickEvent()">Click me</button>
</div>
</template>
<script>
import { eventBus } from '../main'
export default {
data () {
return {
msg: 'Welcome to Your Vue.js App'
}
},
methods: {
emitGlobalClickEvent () {
eventBus.$emit('messageSelected', this.msg)
}
}
}
</script>
User.vue
<template>
<div>
<h2>This is User component</h2>
<user-one></user-one>
</div>
</template>
<script>
import { eventBus } from '../main'
import UserOne from './UserOne.vue'
export default {
created () {
eventBus.$on('messageSelected', msg => {
console.log(msg)
})
},
components: {
UserOne
}
}
</script>
UserOne.vue
<template>
<div>
<h3>We are in UserOne component</h3>
</div>
</template>
<script>
import { eventBus } from '../main'
export default {
created () {
eventBus.$on('messageSelected', msg => {
console.log('From UserOne message !!!')
})
}
}
</script>
I want to get this message : Welcome to Your Vue.js App from Hello.vue in all components, but without #click, if is possible.
You can create another Javascript file which holds an Object with your initial state. Similar to how you define data in your components.
In this file your export your Object and import it in all Components which need access to this shared state. Something along the lines of this:
import Store from 'store';
data() {
return {
store
}
}
This might help:
https://v2.vuejs.org/v2/guide/state-management.html
At this point if you app grows even more in complexity you might also start checking out Vuex which helps to keep track of changes(mutations) inside of your store.
The given example is essential a very oversimplified version of Vuex.
In Angular 1.x, we could insert HTML in real-time by using the HTML tag ng-bind-html, combined with the JavaScript call $sce.trustAsHTML(). This got us 80% of th way there, but wouldn't work when Angular tags were used, such as if you inserted HTML that used ng-repeat or custom directives.
To get that to work, we could use a custom directive that called $compile.
What is the equivalent for all of this in Angular 2? We can bind using [inner-html] but this only works for very simple HTML tags such as <b>. It doesn't transform custom angular 2 directives into functioning HTML elements. (Much like Angular 1.x without the $compile step.) What is the equivalent of $compile for Angular 2?
In Angular2 you should use DynamicComponentLoader to insert some "compiled content" on the page. So for example if you want to compile next html:
<div>
<p>Common HTML tag</p>
<angular2-component>Some angular2 component</angular2-component>
</div>
then you need to create component with this html as a template (let's call it CompiledComponent) and use DynamicComponentLoader to insert this component on the page.
#Component({
selector: 'compiled-component'
})
#View({
directives: [Angular2Component],
template: `
<div>
<p>Common HTML tag</p>
<angular2-component>Angular 2 component</angular2-component>
</div>
`
})
class CompiledComponent {
}
#Component({
selector: 'app'
})
#View({
template: `
<h2>Before container</h2>
<div #container></div>
<h2>After conainer</h2>
`
})
class App {
constructor(loader: DynamicComponentLoader, elementRef: ElementRef) {
loader.loadIntoLocation(CompiledComponent, elementRef, 'container');
}
}
Check out this plunker
UPD You can create component dynamically right before the loader.loadIntoLocation() call:
// ... annotations
class App {
constructor(loader: DynamicComponentLoader, elementRef: ElementRef) {
// template generation
const generatedTemplate = `<b>${Math.random()}</b>`;
#Component({ selector: 'compiled-component' })
#View({ template: generatedTemplate })
class CompiledComponent {};
loader.loadIntoLocation(CompiledComponent, elementRef, 'container');
}
}
I personally don't like it, it's look like a dirty hack to me. But here is the plunker
PS Beware that at this moment angular2 is under active development. So situation can be changed at any time.
DynamicComponentLoader is deprecated, you can use ComponentResolver instead
You could use this directive, add pipes if you need additional data manipulation. It also allows for lazy loading, you don't need it in your case, but it's worth mentioning.
Directive(I found this code and made some changes, you can do that too to make it fit your taste or use it as is):
import { Component, Directive, ComponentFactory, ComponentMetadata, ComponentResolver, Input, ReflectiveInjector, ViewContainerRef } from '#angular/core';
declare var $:any;
export function createComponentFactory(resolver: ComponentResolver, metadata: ComponentMetadata): Promise<ComponentFactory<any>> {
const cmpClass = class DynamicComponent {};
const decoratedCmp = Component(metadata)(cmpClass);
return resolver.resolveComponent(decoratedCmp);
}
#Directive({
selector: 'dynamic-html-outlet',
})
export class DynamicHTMLOutlet {
#Input() htmlPath: string;
#Input() cssPath: string;
constructor(private vcRef: ViewContainerRef, private resolver: ComponentResolver) {
}
ngOnChanges() {
if (!this.htmlPath) return;
$('dynamic-html') && $('dynamic-html').remove();
const metadata = new ComponentMetadata({
selector: 'dynamic-html',
templateUrl: this.htmlPath +'.html',
styleUrls: [this.cssPath]
});
createComponentFactory(this.resolver, metadata)
.then(factory => {
const injector = ReflectiveInjector.fromResolvedProviders([], this.vcRef.parentInjector);
this.vcRef.createComponent(factory, 0, injector, []);
});
}
}
Example how to use it:
import { Component, OnInit } from '#angular/core';
import { DynamicHTMLOutlet } from './../../directives/dynamic-html-outlet/dynamicHtmlOutlet.directive';
#Component({
selector: 'lib-home',
templateUrl: './app/content/home/home.component.html',
directives: [DynamicHTMLOutlet]
})
export class HomeComponent implements OnInit{
html: string;
css: string;
constructor() {}
ngOnInit(){
this.html = './app/content/home/home.someTemplate.html';
this.css = './app/content/home/home.component.css';
}
}
home.component.html:
<dynamic-html-outlet [htmlPath]="html" [cssPath]="css"></dynamic-html-outlet>
After reading a lot, and being close of opening a new topic I decided to answer here just to try to help to others. As I've seen there are several changes with the latest version of Angular 2. (Currently Beta9)
I'll try to share my code in order to avoid the same frustration I had...
First, in our index.html
As usual, we should have something like this:
<html>
****
<body>
<my-app>Loading...</my-app>
</body>
</html>
AppComponent (using innerHTML)
With this property you will be able to render the basic HTML, but you won't be able to do something similar to Angular 1.x as $compile through a scope:
import {Component} from 'angular2/core';
#Component({
selector: 'my-app',
template: `
<h1>Hello my Interpolated: {{title}}!</h1>
<h1 [textContent]="'Hello my Property bound: '+title+'!'"></h1>
<div [innerHTML]="htmlExample"></div>
`,
})
export class AppComponent {
public title = 'Angular 2 app';
public htmlExample = ' <div>' +
'<span [textContent]="\'Hello my Property bound: \'+title"></span>' +
'<span>Hello my Interpolated: {{title}}</span>' +
'</div>'
}
This will render the following:
Hello my Interpolated: Angular 2 app!
Hello my Property bound: Angular 2 app!
Hello my Interpolated: {{title}}
AppComponent Using DynamicComponentLoader
There is a little bug with the docs, documented in here. So if we have in mind that, my code should look now like this:
import {DynamicComponentLoader, Injector, Component, ElementRef, OnInit} from "angular2/core";
#Component({
selector: 'child-component',
template: `
<div>
<h2 [textContent]="'Hello my Property bound: '+title"></h2>
<h2>Hello my Interpolated: {{title}}</h2>
</div>
`
})
class ChildComponent {
title = 'ChildComponent title';
}
#Component({
selector: 'my-app',
template: `
<h1>Hello my Interpolated: {{title}}!</h1>
<h1 [textContent]="'Hello my Property bound: '+title+'!'"></h1>
<div #child></div>
<h1>End of parent: {{endTitle}}</h1>
`,
})
export class AppComponent implements OnInit{
public title = 'Angular 2 app';
public endTitle= 'Bye bye!';
constructor(private dynamicComponentLoader:DynamicComponentLoader, private elementRef: ElementRef) {
// dynamicComponentLoader.loadIntoLocation(ChildComponent, elementRef, 'child');
}
ngOnInit():any {
this.dynamicComponentLoader.loadIntoLocation(ChildComponent, this.elementRef, 'child');
}
}
This will render the following:
Hello my Interpolated: Angular 2 app!
Hello my Property bound: Angular 2 app!
Hello my Property bound: ChildComponent title
Hello my Interpolated: ChildComponent title
End of parent: Bye bye!
I think all you have to do is set the element you want to have compiled html with the [innerHTML]="yourcomponentscopevar"
Angular provided DynamicComponentLoader class for loading html dynamically. DynamicComponentLoader have methods for inserting components. loadIntoLocation is one of them for inserting component.
paper.component.ts
import {Component,DynamicComponentLoader,ElementRef,Inject,OnInit} from 'angular2/core';
import { BulletinComponent } from './bulletin.component';
#Component({
selector: 'paper',
templateUrl: 'app/views/paper.html'
}
})
export class PaperComponent {
constructor(private dynamicComponentLoader:DynamicComponentLoader, private elementRef: ElementRef) {
}
ngOnInit(){
this.dynamicComponentLoader.loadIntoLocation(BulletinComponent, this.elementRef,'child');
}
}
bulletin.component.ts
import {Component} from 'angular2/core';
#Component({
selector: 'bulletin',
templateUrl: 'app/views/bulletin.html'
}
})
export class BulletinComponent {}
paper.html
<div>
<div #child></div>
</div>
Few things you need to take care of :
Don't call loadIntoLocation inside the constructor of class . Component view is not yet created when component constructor is called. You will get error -
Error during instantiation of AppComponent!. There is no component
directive at element [object Object]
Put anchorName #child in html otherwise you will get error.
Could not find variable child
Have a look at this module https://www.npmjs.com/package/ngx-dynamic-template
After a long research, only this thing helped me. The rest of the solutions seems to be outdated.