We Keep Coding

Trigger a function in already mounted Vue component from router-link in parent component

I have a tricky communication issue between a router-link in my parent Vue component and a child component.
I would like to clear an input field on the child component, which is the main Index for my app. This component loads by default.
The parent App component contains the main navigation which contains a router-link routed back to the index like so:
<router-link :to="{ name: 'Index', query: { search: '' }}" class="nav-link">
Index
</router-link>
The Index component contains a search input to filter the index items list. The search value is tracked by the component's data.
data() {
return {
items: [],
tags: [],
search:'',
}
The issue is I cannot seem to clear the search input when the router-link for the Index is clicked. I assume because the Index is already mounted clicking the link cannot trigger any function in the component.
I have tried using $emit by wrapping the link text in <span #click="clearSearch()">, putting the $emit in the clearSearch function and picking it up in the Index, but this apparently doesn't work from parent to child??
As you can see in the router-link above I have also tried passing as query like query: { search: '' } and adding the following to the main.js route configuration.
props(route) {
return { search: route.query.search }
}
This sends the empty string in URL but I still cannot pick it up in the Index component to clear the search input, again I think because it is already mounted.
This seems like it should be an easy thing to do, but I am a bit stumped on it and don't know what else to try. I am still learning Vue so there might be something obvious I am missing. If anyone can help me out on how to achieve this I would much appreciate it. Thanks in advance.

An easy hack would be to use router.push() in a method instead of <router-link> and to make search a prop and clear it from the parent.
This way you can store search in the parent data and clear it on click.
// Parent component
<template>
<div #click="navigate" class="nav-link">
Index
</div>
...
<Index :search="search" />
</template>
<script>
export default {
data() {
return {
search: ''
}
},
methods: {
navigate() {
this.$router.push({ name: 'Index' });
this.search = '';
}
}
}
</script>
// Child component
<template>
{{ search }}
</template>
<script>
export default {
props: {
search: {
type: String,
default: '',
}
}
}
</script>

Trying to avoid mutating a prop that goes 3 levels deep by using $emit

EDIT: Here's a repo I made for easier parsing.
I have a Component that lists products in a datatable. The first column of the table is a link that shows a modal with a form of the product that was clicked (using its ID). I'm using the PrimeVue library for styling and components.
<template>
<Column field="id" headerStyle="width: 5%">
<template #body="slotProps">
<ProductForm :product="slotProps.data" :show="showModal(slotProps.data.id)" />
<a href="#" #click.stop="toggleModal(slotProps.data.id)">
<span class="pi pi-external-link"> </span>
</a>
</template>
</Column>
</template>
<script>
import ProductForm from "./forms/ProductForm";
export default {
data() {
return {
activeModal: 0,
}
},
components: { ProductForm },
methods: {
toggleModal: function (id) {
if (this.activeModal !== 0) {
this.activeModal = 0;
return false;
}
this.activeModal = id;
},
showModal: function (id) {
return this.activeModal === id;
},
},
</script>
The modal is actually a sub component of the ProductForm component (I made a template of the Modal so I could reuse it). So it's 3 components all together (ProductList -> ProductForm -> BaseModal). Here's the product form:
<template>
<div>
<BaseModal :show="show" :header="product.name">
<span class="p-float-label">
<InputText id="name" type="text" :value="product.name" />
<label for="name">Product</label>
</span>
</BaseModal>
</div>
</template>
<script>
import BaseModal from "../_modals/BaseModal";
export default {
props: ["product", "show"],
components: { BaseModal },
data() {
return {};
},
};
</script>
When the modal pops up it uses the ProductForm subcomponent. Here is the BaseModal component:
<template>
<div>
<Dialog :header="header" :visible.sync="show" :modal="true" :closable="true" #hide="doit">
<slot />
</Dialog>
</div>
</template>
<script>
export default {
props: {
show: Boolean,
header: String,
},
methods: {
doit: function () {
let currentShow = this.show;
this.$emit("showModel", currentShow)
},
},
data() {
return {
};
},
};
</script>
I'm passing the product object, and a show boolean that designates if the modal is visible or not from the first component (ProductList) all the way down through the ProductForm component and finally to the BaseModal component. The modal is a PrimeVue component called Dialog. The component actually has it's own property called "closable" which closes the modal with an X button when clicked, that is tied to an event called hide. Everything actually works. I can open the modal and close it. For some reason I have to click the another modal link twice before it opens after the initial.
The issue is when I close a modal, I get the Avoid mutating a prop directly since the value will be overwritten whenever the parent component re-renders. Instead, use a data or computed property based on the prop's value. Prop being mutated: "show" error. I've tried everything to emit to the event and change the original props value there, but the error persists (even from the code above) but I'm not sure if because I'm 3 components deep it won't work. I'm pretty new to using props and slots and $emit so I know I'm doing something wrong. I'm also new to laying out components this deep so I might not even be doing the entire layout correctly. What am I missing?

Well you are emitting the showModel event from BaseModal but you are not listening for it on the parent and forwarding it+listening on grandparent (ProductForm)
But the main problem is :visible.sync="show" in BaseModal. It is same as if you do :visible="show" #update:visible="show = $event" (docs). So when the Dialog is closed, PrimeVue emits update:visible event which is picked by BaseModal component (thanks to the .sync modifier) and causes the mutation of the show prop inside BaseModal and the error message...
Remember to never use prop value directly with v-model or .sync
To fix it, use the prop indirectly via a computed with the setter:
BaseModal
<template>
<div>
<Dialog :header="header" :visible.sync="computedVisible" :modal="true" :closable="true">
<slot />
</Dialog>
</div>
</template>
<script>
export default {
props: {
show: Boolean,
header: String,
},
computed: {
computedVisible: {
get() { return this.show },
set(value) { this.$emit('update:show', value) }
}
},
};
</script>
Now you can add same computed into your ProductForm component and change the template to <BaseModal :show.sync="computedVisible" :header="product.name"> (so when the ProductForm receives the update:show event, it will emit same event to it's parent - this is required as Vue event do not "bubble up" as for example DOM events, only immediate parent component receives the event)
Final step is to handle update:show in the ProductList:
<ProductForm :product="slotProps.data" :show="showModal(slotProps.data.id)" #update:show="toggleModal(slotProps.data.id)"/>

TypeError: Cannot read property '_wrapper' of undefined

I am trying to update the props data sent to a component on a button click to a single component in vue.
Button click triggers an action loads the data from a config. But this throws the error and the error message was not clear. Find the error here https://imgur.com/a/0psUWKr
If I pass the data directly without the button actions, it works fine.
My Main component
<template>
<div>
<MyList v-if="listItems" :elements="listItems"/>
<button #click="showSlider">Show Slider</button>
</div>
</template>
<script>
// imports the components and config files
export default {
name: "ListView",
data() {
return {
listItems: []
};
},
components: {
MyList
},
methods: {
showSlider: function() {
this.listItems.push(configs['elements'])
},
</script>
NOTE: If i provide the data to listItems by default it works
And MyList file
<template>
<ul>
<li v-for="each in elements" :key="each.id">
{{each.name}}
</li>
</ul>
<template>
<script>
// imports the components and config files
export default {
name: "MyList",
props: {
elements: {
type: Array
}
}
</script>

It should work, in general. But in my case, the issue is with push in the following function.
showSlider: function() {
this.listItems.push(configs['elements'])
},
Storing the same from Vuex and using dispatcher to update the same works like a charm. And I use computed property to load the state from the vueX and pass it to MyList

VueJS 2: Catch event of direct child component

I'm currently trying to get a simple Tabs/Tab component up and running.
It seems like something in the event handling mechanism has changed, therefore I can't get it to work.
Current implementation:
Tabs.vue
<template>
<div class="tabbed-pane">
<ul class="tab-list">
<li class="tab" v-for="tab in tabs" #click="activateTab(tab)">{{ tab.header }}</li>
</ul>
<slot></slot>
</div>
</template>
<script>
import hub from '../eventhub';
export default {
props: [],
data() {
return {
tabs: []
}
},
created() {
this.$on('tabcreated', this.registerTab)
},
methods: {
registerTab(tab) {
this.tabs.push(tab);
},
activateTab(tab) {
}
}
}
</script>
Tab.vue
<template>
<div class="tab-pane" v-show="active">
<slot></slot>
</div>
</template>
<script>
import hub from '../eventhub';
export default {
props: {
'header': String
},
data() {
return {
active: false
}
},
mounted() {
this.$emit('tabcreated', this);
}
}
</script>
eventhub.js
import Vue from 'vue';
export default new Vue();
View
<tabs>
<tab header="Test">
First Tab
</tab>
<tab header="Test2">
Second Tab
</tab>
<tab header="Test3">
Third Tab
</tab>
</tabs>
I've tried the following things:
use a Timeout for the $emit to test if it's a timing issue (it is
not)
use #tabcreated in the root element of the Tabs components
template
It works if...
... I use the suggested "eventhub" feature (replacing this.$on and
this.$emit with hub.$on and hub.$emit)
but this is not suitable for me, as I want to use the Tabs component multiple times on the same page, and doing it with the "eventhub" feature wouldn't allow that.
... I use this.$parent.$emit
but this just feels weird and wrong.
The documentation states that it IS possible to listen for events triggered by $emit on direct child components
https://v2.vuejs.org/v2/guide/migration.html#dispatch-and-broadcast-replaced
Does anyone have an Idea?

You're right, in vue 2, there is no more $dispatch. $emit could work for a single component but it will be scoped to himself (this). The recommended solution is to use a global event manager, the eventhub.
the eventhub can be stored in the window object to be used anywhere without import, I like to declare in my main.js file like this:
window.bus = new Vue()
and then in whatever component:
bus.$emit(...)
bus.$on(...)
It works just the same as this.$root.$emit / this.$root.$on. You said it works when you call this.$parent.$emit, but this code, simulate a scoped emit in the parent component but fired from the child, not good.
What I understand in your code is that you want to have an array of created tabs, but to do what with them ?
Instead of storing the tab instance in the parent and then activate from the parent, you should think about a more functional way.
The activateTab method should be declared on the tab component and manage the instanciation through the data, something like:
Tabs.vue
<template>
<div class="tabbed-pane">
<ul class="tab-list">
<tab v-for="tab in tabs" :header="tab.header"></tab>
</ul>
</div>
</template>
<script>
import hub from '../eventhub';
import Tab from 'path/to/Tab.vue';
export default {
components: [Tab],
props: [],
data() {
return {
tabs: ['First Tab', 'Second Tab', 'Third Tab']
}
}
}
</script>
Tab.vue
<template>
<div class="tab tab-pane" #click:activeTab()>
<span v-show="active">Activated</span>
<span>{{ header }}</span>
</div>
</template>
<script>
import hub from '../eventhub';
export default {
props: {
'header': String
},
data() {
return {
active: false
}
},
methods: {
activeTab () {
this.active = true
}
}
}
</script>
This way, your Tab is more independant. For parent/child communication keep this in mind :
parent to child > via props
child to parent > via $emit (global bus)
If you need a more complexe state management you definitely should take a look at vuex.
Edit
Tabs.vue
<template>
<div class="tabbed-pane">
<ul class="tab-list">
<tab v-for="tabData in tabs" :custom="tabData"></tab>
</ul>
</div>
</template>
<script>
import Tab from 'path/to/Tab.vue';
export default {
components: [Tab],
props: [],
data() {
return {
tabs: [
{foo: "foo 1"},
{foo: "foo 2"}
{foo: "foo 3"}
]
}
}
}
</script>
Tab.vue
<template>
<div class="tab tab-pane" #click:activeTab()>
<span v-show="active">Activated</span>
<span>{{ custom.foo }}</span>
</div>
</template>
<script>
export default {
props: ['custom'],
data() {
return {
active: false
}
},
methods: {
activeTab () {
this.active = true
}
}
}
</script>

This is what I don't like about VueJS (2), there is no convenient way of catching events emitted from child components to the parent component.
Anyways an alternative to this is if you do not want to use the eventhub approach, specially if you are only going to have an event communication between related components ( child and parent ) and not with non-related components, then you can do these steps.
reference your parent vue component on its data property (very important, you can't just pass this to the child component)
pass that parent vue component reference as an attribute to the child component ( make sure to bind it)
trigger the appropriate event of the parent component inside the child component whenever a desired event is emitted
Pseudo code
// Parent vue component
Vue.component( 'parent_component' , {
// various codes here ...
data : {
parent_component_ref : this // reference to the parent component
},
methods : {
custom_event_cb : function() {
// custom method to execute when child component emits 'custom_event'
}
}
// various codes here ...
} );
// Parent component template
<div id="parent_component">
<child_component :parent_component_ref="parent_component_ref"></child_component>
</div>
// Child component
Vue.component( 'child_component' , {
// various codes here ...
props : [ 'parent_component_ref' ],
mounted : function() {
this.$on( 'custom_event' , this.parent_component_ref.custom_event_cb );
this.$emit( 'custom_event' );
},
// You can also, of course, emit the event on events inside the child component, ex. button click, etc..
} );
Hope this helps anyone.

Use v-on="$listeners", which is available since Vue v2.4.0. You can then subscribe to any event you want on the parent, see fiddle.
Credit to BogdanL from Vue Support # Discord.

How to get data resolved in parent component

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