I have the following component:
Vue.component('visible-filter', {
template: `
<span class="text-muted"
#mouseenter="changeClassMouseenter($event)"
#mouseout="changeClassMouseout($event)"
#click="countryTest(filter)"
#clicked="clicked = true"
v-model="clicked"
><slot></slot></span>
`,
props: ['filter', 'clicked'],
methods: {
changeClassMouseenter(event) {
console.log(this.clicked);
event.target.classList.remove('text-muted')
},
changeClassMouseout(event) {
event.target.classList.add('text-muted')
},
countryTest(filter) {
Event.$emit('clicked');
Event.$emit('country-filter', filter);
}
}
});
The Event in the main instance:
Event.$on('clicked', () => {
this.clicked = true;
})
The data in the main instance:
data: {
clicked: false
},
The thing I want to do:
When I click on the element, I want to set the clicked property to true (for that element), and for the rest of the elements I want to set it to false; Also I want to check if the clicked is true/false when the mouseenter/mouseout event is fired.
How can I achive this?
You should not change the parent from child.
To make communication between parent and child (and child->parent as well) you can/should set up the events.
Emit the event in child component. Nice examples here: https://v2.vuejs.org/v2/guide/components.html#Using-v-on-with-Custom-Events
Listen to event in your parent using <child-component #yourEventName='eventHandler(data)'>
Handle data in your parent, so add eventHandler(data) into your methods and do whatever you want with your data.
Related
I have created a table component which accept dynamic data (th, tr, td,...).
Table data (td) could be a dynamic component as below:
<td>
<component
:is="data.content"
:colspan="data.colspan"
v-bind="data.props"
v-on="data.events"/>
</td>
...
export default {
name: "DynamicTable",
props: {
...
isLoading : { // loading slot will be used if true
type: Boolean,
default: false
}
}
}
I feed required data in another component like this:
<other-html-elements/>
<dynamic-table
:table-heads="tableHeads"
:table-rows="tableRows"
:is-loading="isLoading">
...
computed: { ...
tableRows () {...
new TableData(CancelOrderButton, 'component', {
props: {
order
},
events: {
'updateLoadingStatus': this.updateLoadingStatus
}
})
...
methods: { ...
updateLoadingStatus (status) {
this.isLoading = status
}
and here is my CancelOrderButton:
methods: {
cancelOrder () {
this.$emit('updateLoadingStatus', true)
somePromise().finally(() => {
this.$emit('updateLoadingStatus', false)
})
once I click on a button and invoke the cancelOrder method, the updateLoadingStatus will be emitted without any problem. and after the promise settled, it will be emitted again. but the handler will not triggered.
I have checked everything. I'm sure that events are emitted. this problem will be fixed when I move the second emit statement out of the finally block or I if do not pass isLoading as a props for the dynamicTable.
Try setting the prop for that emit like this:
<dynamic-table
:table-heads="tableHeads"
:table-rows="tableRows"
#update-loading-status="updateLoadingStatus"
:is-loading="isLoading">
And calling that emit like this (although it should work as you have it):
this.$emit('update-loading-status', true)
Also you can define them in a general way and use them in the component you want:
https://v2.vuejs.org/v2/guide/custom-directive.html
Working with VUE.JS...
Having a 'theParent' component with two childs: 'theForm' and 'theButtons'.
(This is a simplification of more complex scenario).
In 'theButtons' exists a 'Clear' button to clean fields of 'theForm' form.
I am able to pass the event from 'theButtons' to 'theParent', but not from 'theParent' to 'theForm' ¿?
Within 'theButtons':
<b-button v-on:click="clean()">Clear</b-button>
methods: {
clean() {
this.$emit('clean');
}
},
Within 'theParent':
<theForm />
<theButtons v-on:clean="clean"/>
methods: {
clean() {
this.$emit('theForm.clean'); //Here is the point I dont know what to put
}
},
Within 'theForm':
methods: {
clean() {
alert("This is what I want to get executed!!");
}
},
Add a ref to the TheForm component then run its method from parent :
<theForm ref="form" />
<theButtons v-on:clean="clean"/>
methods: {
clean() {
this.$refs.form.clean(); //clean should be a method in theForm component.
}
},
Or you could add a prop to theForm component which could be updated in parent and watch in child component to clean the form :
<theForm :clean="clean" />
<theButtons v-on:clean="clean"/>
data(){
return {
clean:false
}
},
methods: {
clean() {
this.clean=clean;
}
},
inside theForm :
props:['clean'],
watch:{
clean(val){
if(val){
this.clean()
}
}
}
One thing to keep in mind is the flow of passing data from child to parent and vice versa.
In a nutshell:
Parent => Child: if you want to pass data from parent to child, use props.
Child => Parent: if you want to pass data from child to parent, use events.
One solution to your problem is to have <b-button> as a child to the <theForm> as follows:
<theForm v-on:clean="cleanForm">
<!-- form children -->
....
<theButton />
....
</theForm>
Another solution is to have an event bus that passes events between components which is totally unnecessary in your case.
Reference: https://v3.vuejs.org/guide/component-basics.html#passing-data-to-child-components-with-props
https://v3.vuejs.org/guide/component-basics.html#listening-to-child-components-events
I have a child and a parent component.
The flow is: In parent I have "Save changes"-> I have one method that update it -> also in child I have an method to update a part of the component , but if I have duplicate value first emits the Update from parent and after that I got error from Child, and I want to await for a answer from child until I update parent component.
Parent:
<b-btn #click="updateCustomer">Save Changes</b-btn>
<display-pr #duplicateValue="valueDuplicate"></display-pr>
updateCustomer() {
if(this.duplicateValue){
//error message
}else{
//do something
}
}
valueDuplicate(duplicateValue) {
this.duplicateValue = duplicateValue;
},
Child
updateCustomerName(){
//find if I have duplicate and if I have let duplicate= true;
if(duplicate){
this.$emit('duplicateValue',duplicateValue);
}
else {
//post
}
}
You can disable "Save Changes" button for click event at parent component until finishing up checking duplication at child component. if you check duplication from network call, you should use asynchronous javascript paradigm.
parent
<template>
<b-btn #click="updateCustomer">Save Changes :disabled="isSaveBtnDisabled"</b-btn>
<display-pr #duplicateValue="valueDuplicate"></display-pr>
<child-component #checkDuplicates="changeSaveBtnStatus"></child-component>
</template>
<script>
data: () => {
isSaveBtnDisabled: false
},
methods: {
changeSaveBtnStatus: (event) => {
this.isSaveBtnDisabled = event;
}
}
</script>
Child
updateCustomerName: () => {
this.$emit('checkDuplicates', true);
/*
* Here is code statements the checking duplicates and enable save button by calling
* this.$emit('checkDuplicates', false);
*
*/
this.$emit('checkDuplicates', false);
if(duplicate){
this.$emit('duplicateValue',duplicateValue);
}
else {/***post ***/}
}
I have a component as defined by the following template, assume it's called CompositeComponent:
<template>
<div class="item-and-qualifiers-selector">
<special-list
:props="someProps"
></special-list>
<another-special-list
:id="'anotherSpecialList1'"
:list-items="someListItems"
></another-special-list>
<another-special-list
:id="'anotherSpecialList2'"
:list-items="someMoreListItems"
></another-special-list>
</div>
</template>
The CompositeComponent in constructed of two different components, SpecialList and AnotherSpecialList, where AnotherSpecialList appears twice within the structure of the CompositeComponent. Assume the following basic component design for AnotherSpecialList:
export default {
name: 'AnotherSpecialList',
props: {
listItems: { type: Array, required: true },
id: { type: String, required: true }
},
data() {
return {
activeListItem: null
};
},
created() {
document.addEventListener('focusin', this.focusChanged);
},
methods: {
focusChanged() {
if (document.activeElement.id === 'anotherSpecialList1') {
console.log('Focussed on the first special list');
this.activeListItem = this.listItems[0];
} else if (document.activeElement.id === 'anotherSpecialList2') {
console.log('Focussed on the second special list');
this.activeListItem = this.listItems[0];
}
}
}
};
</script>
When the DOM's current focus is the SpecialList, I want to tab from the SpecialList into the first instance of AnotherSpecialList and assign the activeListItem of AnotherSpecialList where id === anotherSpecialList1 to listItems[0], i.e., this.activeListItem = listItems[0]. Then, similarly, when the DOM's current focus is the AnotherSpecialList where id === anotherSpecialList1, I want to tab from that instance into the second instance of AnotherSpecialList where id === anotherSpecialList2 and assign the activeListItem of AnotherSpecialList where id === anotherSpecialList2 to listItems[0].
Currently, I've got a listener attached to focusin which is created in mounted, which is bound to focusChanged. I'm fetching the document's activeElement and checking the id against the two values that have been specified, anotherSpecialList1 and anotherSpecialList2. The problem I'm facing with the logic of this.activeListItem = this.listItems[0]; is that it is happening for both instances of AnotherSpecialList. Is there a way where I can select a specific instance of AnotherSpecialList and only execute the logic on the instance that matches the one that is the current focus of the DOM?
How do I access $refs inside computed? It's always undefined the first time the computed property is run.
Going to answer my own question here, I couldn't find a satisfactory answer anywhere else. Sometimes you just need access to a dom element to make some calculations. Hopefully this is helpful to others.
I had to trick Vue to update the computed property once the component was mounted.
Vue.component('my-component', {
data(){
return {
isMounted: false
}
},
computed:{
property(){
if(!this.isMounted)
return;
// this.$refs is available
}
},
mounted(){
this.isMounted = true;
}
})
I think it is important to quote the Vue js guide:
$refs are only populated after the component has been rendered, and they are not reactive. It is only meant as an escape hatch for direct child manipulation - you should avoid accessing $refs from within templates or computed properties.
It is therefore not something you're supposed to do, although you can always hack your way around it.
If you need the $refs after an v-if you could use the updated() hook.
<div v-if="myProp"></div>
updated() {
if (!this.myProp) return;
/// this.$refs is available
},
I just came with this same problem and realized that this is the type of situation that computed properties will not work.
According to the current documentation (https://v2.vuejs.org/v2/guide/computed.html):
"[...]Instead of a computed property, we can define the same function as a method. For the end result, the two approaches are indeed exactly the same. However, the difference is that computed properties are cached based on their reactive dependencies. A computed property will only re-evaluate when some of its reactive dependencies have changed"
So, what (probably) happen in these situations is that finishing the mounted lifecycle of the component and setting the refs doesn't count as a reactive change on the dependencies of the computed property.
For example, in my case I have a button that need to be disabled when there is no selected row in my ref table.
So, this code will not work:
<button :disabled="!anySelected">Test</button>
computed: {
anySelected () {
if (!this.$refs.table) return false
return this.$refs.table.selected.length > 0
}
}
What you can do is replace the computed property to a method, and that should work properly:
<button :disabled="!anySelected()">Test</button>
methods: {
anySelected () {
if (!this.$refs.table) return false
return this.$refs.table.selected.length > 0
}
}
For others users like me that need just pass some data to prop, I used data instead of computed
Vue.component('my-component', {
data(){
return {
myProp: null
}
},
mounted(){
this.myProp= 'hello'
//$refs is available
// this.myProp is reactive, bind will work to property
}
})
Use property binding if you want. :disabled prop is reactive in this case
<button :disabled="$refs.email ? $refs.email.$v.$invalid : true">Login</button>
But to check two fields i found no other way as dummy method:
<button :disabled="$refs.password ? checkIsValid($refs.email.$v.$invalid, $refs.password.$v.$invalid) : true">
{{data.submitButton.value}}
</button>
methods: {
checkIsValid(email, password) {
return email || password;
}
}
I was in a similar situation and I fixed it with:
data: () => {
return {
foo: null,
}, // data
And then you watch the variable:
watch: {
foo: function() {
if(this.$refs)
this.myVideo = this.$refs.webcam.$el;
return null;
},
} // watch
Notice the if that evaluates the existence of this.$refs and when it changes you get your data.
What I did is to store the references into a data property. Then, I populate this data attribute in mounted event.
data() {
return {
childComps: [] // reference to child comps
}
},
methods: {
// method to populate the data array
getChildComponent() {
var listComps = [];
if (this.$refs && this.$refs.childComps) {
this.$refs.childComps.forEach(comp => {
listComps.push(comp);
});
}
return this.childComps = listComps;
}
},
mounted() {
// Populates only when it is mounted
this.getChildComponent();
},
computed: {
propBasedOnComps() {
var total = 0;
// reference not to $refs but to data childComps array
this.childComps.forEach(comp => {
total += comp.compPropOrMethod;
});
return total;
}
}
Another approach is to avoid $refs completely and just subscribe to events from the child component.
It requires an explicit setter in the child component, but it is reactive and not dependent on mount timing.
Parent component:
<script>
{
data() {
return {
childFoo: null,
}
}
}
</script>
<template>
<div>
<Child #foo="childFoo = $event" />
<!-- reacts to the child foo property -->
{{ childFoo }}
</div>
</template>
Child component:
{
data() {
const data = {
foo: null,
}
this.$emit('foo', data)
return data
},
emits: ['foo'],
methods: {
setFoo(foo) {
this.foo = foo
this.$emit('foo', foo)
}
}
}
<!-- template that calls setFoo e.g. on click -->