Related
While rewriting my VueJs project in typescript, I came across a TypeScript error.
This is a part of the component that has a custom v-model.
An input field in the html has a ref called 'plate' and I want to access the value of that. The #input on that field calls the update method written below.
Typescript is complaining that value does not exist on plate.
#Prop() value: any;
update() {
this.$emit('input',
plate: this.$refs.plate.value
});
}
template:
<template>
<div>
<div class="form-group">
<label for="inputPlate" class="col-sm-2 control-label">Plate</label>
<div class="col-sm-10">
<input type="text" class="form-control" id="inputPlate" ref="plate" :value="value.plate" #input="update">
</div>
</div>
</div>
</template>
You can do this:
class YourComponent extends Vue {
$refs!: {
checkboxElement: HTMLFormElement
}
someMethod () {
this.$refs.checkboxElement.checked
}
}
From this issue: https://github.com/vuejs/vue-class-component/issues/94
Edit - 2021-03 (Composition API)
Updating this answer because Vue 3 (or the composition API plugin if you're using Vue 2) has some new functions.
<template>
<div ref="root">This is a root element</div>
</template>
<script lang="ts">
import { ref, onMounted, defineComponent } from '#vue/composition-api'
export default defineComponent({
setup() {
const root = ref(null)
onMounted(() => {
// the DOM element will be assigned to the ref after initial render
console.log(root.value) // <div>This is a root element</div>
})
return {
root
}
}
})
</script>
Edit - 2020-04:
The vue-property-decorator library provides #Ref which I recommend instead of my original answer.
import { Vue, Component, Ref } from 'vue-property-decorator'
import AnotherComponent from '#/path/to/another-component.vue'
#Component
export default class YourComponent extends Vue {
#Ref() readonly anotherComponent!: AnotherComponent
#Ref('aButton') readonly button!: HTMLButtonElement
}
Original Answer
None of the above answers worked for what I was trying to do. Adding the following $refs property wound up fixing it and seemed to restore the expected properties. I found the solution linked on this github post.
class YourComponent extends Vue {
$refs!: {
vue: Vue,
element: HTMLInputElement,
vues: Vue[],
elements: HTMLInputElement[]
}
someMethod () {
this.$refs.<element>.<attribute>
}
}
son.vue
const Son = Vue.extend({
components: {},
props: {},
methods: {
help(){}
}
...
})
export type SonRef = InstanceType<typeof Son>;
export default Son;
parent.vue
<son ref="son" />
computed: {
son(): SonRef {
return this.$refs.son as SonRef;
}
}
//use
this.son.help();
This worked for me: use
(this.$refs.<refField> as any).value or (this.$refs.['refField'] as any).value
Avoid using bracket < > to typecast because it will conflict with JSX.
Try this instead
update() {
const plateElement = this.$refs.plate as HTMLInputElement
this.$emit('input', { plate: plateElement.value });
}
as a note that I always keep remembering
Typescript is just Javascript with strong typing capability to ensure type safety. So (usually) it doesn't predict the type of X (var, param, etc) neither automatically typecasted any operation.
Also, another purpose of the typescript is to make JS code became clearer/readable, so always define the type whenever is possible.
Maybe it will be useful to someone. It looks more beautiful and remains type support.
HTML:
<input ref="inputComment" v-model="inputComment">
TS:
const inputValue = ((this.$refs.inputComment as Vue).$el as HTMLInputElement).value;
In case of custom component method call,
we can typecast that component name, so it's easy to refer to that method.
e.g.
(this.$refs.annotator as AnnotatorComponent).saveObjects();
where AnnotatorComponent is class based vue component as below.
#Component
export default class AnnotatorComponent extends Vue {
public saveObjects() {
// Custom code
}
}
With Vue 3 and the Options API, this is what worked for me:
<script lang="ts">
import {defineComponent} from 'vue';
export default defineComponent({
methods: {
someAction() {
(this.$refs.foo as HTMLInputElement).value = 'abc';
},
},
});
</script>
The autocomplete doesn't bring the foo property from $refs because it's defined in the template, and apparently there's no information inferred from it.
However, once you force the casting of .foo to the HTML element type, everything works from there on, so you can access any element property (like .value, in the example above).
Make sure to wrap your exports with Vue.extend() if you are converting your existing vue project from js to ts and want to keep the old format.
Before:
<script lang="ts">
export default {
mounted() {
let element = this.$refs.graph;
...
After:
<script lang="ts">
import Vue from "vue";
export default Vue.extend({
mounted() {
let element = this.$refs.graph;
...
I found a way to make it work but it is ugly in my opinion.
Feel free to give other/better suggestions.
update() {
this.$emit('input', {
plate: (<any>this.$refs.plate).value,
});
}
I spent a LONG time trying to find an answer to this using Vue 3, TypeScript with class components and (as it happens, although not relevant to this) TipTap. Found the answer from bestRenekton above which finally solved it, but it needed tweaking. I'm pretty sure this is TypeScript specific.
My child component has this at the start:
export default class WhealEditor extends Vue {
It includes this method (the one I want to call from the parent):
doThis(what: string) {
console.log('Called with ' + what)
}
And this right at the end:
export type EditorRef = InstanceType<typeof WhealEditor>
</script>
So this announces to any consumer of the child component that it can access it using the variable EditorRef. The parent component includes the child component in the template:
<WhealEditor ref="refEditor" />
The parent component then imports ref, and the child component and the exposed object:
import { ref } from 'vue'
import WhealEditor, { EditorRef } from './components/WhealEditor.vue'
I then have a method to get this object:
getEditor(): EditorRef {
// gets a reference to the child component
return this.$refs.refEditor as EditorRef
}
Finally, I can handle events - for example:
processButton(msg: string) {
// runs method in child component
this.getEditor().doThis(msg)
Like everything else to do with client script, it's so much harder than I expected!
While rewriting my VueJs project in typescript, I came across a TypeScript error.
This is a part of the component that has a custom v-model.
An input field in the html has a ref called 'plate' and I want to access the value of that. The #input on that field calls the update method written below.
Typescript is complaining that value does not exist on plate.
#Prop() value: any;
update() {
this.$emit('input',
plate: this.$refs.plate.value
});
}
template:
<template>
<div>
<div class="form-group">
<label for="inputPlate" class="col-sm-2 control-label">Plate</label>
<div class="col-sm-10">
<input type="text" class="form-control" id="inputPlate" ref="plate" :value="value.plate" #input="update">
</div>
</div>
</div>
</template>
You can do this:
class YourComponent extends Vue {
$refs!: {
checkboxElement: HTMLFormElement
}
someMethod () {
this.$refs.checkboxElement.checked
}
}
From this issue: https://github.com/vuejs/vue-class-component/issues/94
Edit - 2021-03 (Composition API)
Updating this answer because Vue 3 (or the composition API plugin if you're using Vue 2) has some new functions.
<template>
<div ref="root">This is a root element</div>
</template>
<script lang="ts">
import { ref, onMounted, defineComponent } from '#vue/composition-api'
export default defineComponent({
setup() {
const root = ref(null)
onMounted(() => {
// the DOM element will be assigned to the ref after initial render
console.log(root.value) // <div>This is a root element</div>
})
return {
root
}
}
})
</script>
Edit - 2020-04:
The vue-property-decorator library provides #Ref which I recommend instead of my original answer.
import { Vue, Component, Ref } from 'vue-property-decorator'
import AnotherComponent from '#/path/to/another-component.vue'
#Component
export default class YourComponent extends Vue {
#Ref() readonly anotherComponent!: AnotherComponent
#Ref('aButton') readonly button!: HTMLButtonElement
}
Original Answer
None of the above answers worked for what I was trying to do. Adding the following $refs property wound up fixing it and seemed to restore the expected properties. I found the solution linked on this github post.
class YourComponent extends Vue {
$refs!: {
vue: Vue,
element: HTMLInputElement,
vues: Vue[],
elements: HTMLInputElement[]
}
someMethod () {
this.$refs.<element>.<attribute>
}
}
son.vue
const Son = Vue.extend({
components: {},
props: {},
methods: {
help(){}
}
...
})
export type SonRef = InstanceType<typeof Son>;
export default Son;
parent.vue
<son ref="son" />
computed: {
son(): SonRef {
return this.$refs.son as SonRef;
}
}
//use
this.son.help();
This worked for me: use
(this.$refs.<refField> as any).value or (this.$refs.['refField'] as any).value
Avoid using bracket < > to typecast because it will conflict with JSX.
Try this instead
update() {
const plateElement = this.$refs.plate as HTMLInputElement
this.$emit('input', { plate: plateElement.value });
}
as a note that I always keep remembering
Typescript is just Javascript with strong typing capability to ensure type safety. So (usually) it doesn't predict the type of X (var, param, etc) neither automatically typecasted any operation.
Also, another purpose of the typescript is to make JS code became clearer/readable, so always define the type whenever is possible.
Maybe it will be useful to someone. It looks more beautiful and remains type support.
HTML:
<input ref="inputComment" v-model="inputComment">
TS:
const inputValue = ((this.$refs.inputComment as Vue).$el as HTMLInputElement).value;
In case of custom component method call,
we can typecast that component name, so it's easy to refer to that method.
e.g.
(this.$refs.annotator as AnnotatorComponent).saveObjects();
where AnnotatorComponent is class based vue component as below.
#Component
export default class AnnotatorComponent extends Vue {
public saveObjects() {
// Custom code
}
}
With Vue 3 and the Options API, this is what worked for me:
<script lang="ts">
import {defineComponent} from 'vue';
export default defineComponent({
methods: {
someAction() {
(this.$refs.foo as HTMLInputElement).value = 'abc';
},
},
});
</script>
The autocomplete doesn't bring the foo property from $refs because it's defined in the template, and apparently there's no information inferred from it.
However, once you force the casting of .foo to the HTML element type, everything works from there on, so you can access any element property (like .value, in the example above).
Make sure to wrap your exports with Vue.extend() if you are converting your existing vue project from js to ts and want to keep the old format.
Before:
<script lang="ts">
export default {
mounted() {
let element = this.$refs.graph;
...
After:
<script lang="ts">
import Vue from "vue";
export default Vue.extend({
mounted() {
let element = this.$refs.graph;
...
I found a way to make it work but it is ugly in my opinion.
Feel free to give other/better suggestions.
update() {
this.$emit('input', {
plate: (<any>this.$refs.plate).value,
});
}
I spent a LONG time trying to find an answer to this using Vue 3, TypeScript with class components and (as it happens, although not relevant to this) TipTap. Found the answer from bestRenekton above which finally solved it, but it needed tweaking. I'm pretty sure this is TypeScript specific.
My child component has this at the start:
export default class WhealEditor extends Vue {
It includes this method (the one I want to call from the parent):
doThis(what: string) {
console.log('Called with ' + what)
}
And this right at the end:
export type EditorRef = InstanceType<typeof WhealEditor>
</script>
So this announces to any consumer of the child component that it can access it using the variable EditorRef. The parent component includes the child component in the template:
<WhealEditor ref="refEditor" />
The parent component then imports ref, and the child component and the exposed object:
import { ref } from 'vue'
import WhealEditor, { EditorRef } from './components/WhealEditor.vue'
I then have a method to get this object:
getEditor(): EditorRef {
// gets a reference to the child component
return this.$refs.refEditor as EditorRef
}
Finally, I can handle events - for example:
processButton(msg: string) {
// runs method in child component
this.getEditor().doThis(msg)
Like everything else to do with client script, it's so much harder than I expected!
Let's say I have a component called child. I have data there that I want to access in my parent component. I want to emit an event in the childs mount: this.$emit('get-data', this.data) before finally retrieving it in the parent mount. Is this possible to do / practical? If it is how can one achieve it? If not, what are some better alternatives?
Cheers.
I am not aware if being able to listen for $emit'd data, from a child mount(), inside a parent mount(). You need to bind the listener to the child component within the parent template. Typical example using SFC
Child.vue:
export default{
name: 'child',
mount(){
this.$emit('get-data', this.data);
}
}
Parent.vue:
<template>
<div>
<child v-on:get-data="doSomething"></child>
</div>
</template>
<script>
import Child from './Child';
export default{
name: 'parent',
components: { Child },
methods(){
doSomething(data){
//Do something with data.
}
}
}
</script>
An alternative way to pass data from a child to a parent is scoped slots. I think that is more appropriate than events in your case (only pass data without any relation to a real event). But I'm not sure that I fully understood you.
I would use the created hook not mounted because you only need access to reactive data and events. You could emit the whole child component and then drill into its data as needed.
template
<child-component #emit-event="handleEvent">
{{ parentData }}
</child-component>
child
Vue.component('child-component', {
template: '<div><slot/></div>',
data() {
return {
childData: 'childData',
}
},
created() {
this.$emit('emit-event', this)
}
})
parent
new Vue({
el: "#app",
data: {
parentData: undefined,
},
methods: {
handleEvent({ childData }) {
this.parentData = childData
}
}
})
Check out this fiddle
How can I be able to call filter of parent using single file component. Below are my code.
app.js
import computed from '../vue/mixins/computed.js';
import filters from '../vue/mixins/filters.js';
import methods from '../vue/mixins/methods.js';
const app = new Vue({
el: '#app',
mixins:[
computed,
filters,
methods
],
mounted: function() {
}
});
home.vue
<template>
<div class="home-content">
<h3>{{home | uppercase}}</h3>
</div>
</template>
<script type="text/javascript">
export default {
data: function() {
return {
home: 'home'
}
},
mounted: function() {
this.$parent.$options.methods.makeConsole();
}
}
</script>
It's giving me this warning in console "Failed to resolve filter: uppercase"
You should just make the filter global available before starting the root instance with
Vue.filter('uppercase', uppercase);
Where uppercase can be a simple function like
function uppercase(str)
return str.uppercase();
}
That would be the most simple and reliable way to use the filter on all vue components;
If you import your filters to your parent via mixins why don't you use that mixin in the child?
Please do not use the this.$parent-method as it makes your child component statical dependend of that parent.
To use the $parent approach you may need to declare the filter function from the parent as a filter in the child:
filters:{
uppercase: this.$parent.$options.filters.uppercase
}
There is no point. Just include your mixin in the child as well. A component should ideally be autonomous, and not aware of where it is in the hierarchy of components (at least not the ones above or on the same level.
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();