Develop Reference

Click Button in Parent, get data from Child to Parent and use it in a method (Vue 3)

I'm working with Vue3 and Bootstrap 5.
MY PROBLEM: I want to click a button in my parent.vue. And after clicking this I want to have the data from my child.vue inside of the method in my parent.vue - method .
But my data is always empty, except I need another ```setTimeout"-function. But actually I don't want to use it.
I think there is a better solution for the props Boolean as well..
If there are any question left regarding my problem, please ask me!
Thanks for trying helping me out!
PARENT:
<template>
<Child :triggerFunc="triggerFunc" #childData="childData"/>
<button type="button" class="btn btn-success" #click="get_data()">Get Data</button>
</template>
<script>
export default {
data() {
return {
triggerFunc: false,
c_data: [],
}
},
methods: {
childData(data) {
this.c_data = data;
},
get_data() {
this.triggerFunc = true;
setTimeout(() => {
this.triggerFunc = false;
}, 50);
console.log(this.c_data);
//HERE I WANT TO USE "C_DATA" BUT OF COURSE IT's EMPTY. WITH ANOTHER SET_TIMEOUT IT WOULD WORK
//BUT I DON'T WANT TO USE IT. BUT WITHOUT IT'S EMPTY.
//LIKE THIS IT WOULD WORK BUT I DON'T WANT IT LIKE THAT
setTimeout(() => {
console.log(this.c_data);
}, 50);
}
},
}
</script>
CHILD:
<template>
<!-- SOME BUTTONS, INPUTS, ETC. IN HERE -->
</template>
<script>
export default {
data() {
return {
input1: "",
input2: "",
}
},
props: {
triggerFunc: Boolean,
},
triggerFunc(triggerFunc) {
if(triggerFunc == true) {
this.save_data()
}
}
methods: {
save_data() {
var data = [
{
Input1: this.input1,
Input2: this.input2
},
]
this.$emit("childData", data);
},
},
}
</script>

Parent can very well hold/own the data of it's children. In that case, the children only render/display the data. Children need to send events up to the parent to update that data. (Here parent is the Key component and child is a Helper for the parent.)
So, here parent always has the master copy of the child's data in its own data variables.
Also, you are using # for binding properties, which is wrong. # is for event binding. For data binding use ':' which is a shorthand for v-bind:
You can just say :childData=c_data
PS: You seem to be getting few of the basics wrong. Vue is reactive and automatically binds the data to the variables. So, you don't have to do this much work. Please look at some basic Vue examples.
Refer: https://sky790312.medium.com/about-vue-2-parent-to-child-props-af3b5bb59829
Edited code:
PARENT:
<template>
<Child #saveClick="saveChildData" :childData="c_data" />
</template>
<script>
export default {
data() {
return {
c_data: [{Input1:"", Input2:""}]
}
},
methods: {
saveChildData(incomingData) {
//Either set the new value, or copy all elements.
this.c_data = incomingData;
}
},
}
</script>
CHILD:
<template>
<!-- SOME BUTTONS, INPUTS, ETC. IN HERE -->
<!-- Vue will sync data to input1, input2. On button click we can send data to parent. -->
<button #click.prevent="sendData" />
</template>
<script>
export default {
props:['childData'],
data() {
return {
input1: "",
input2: "",
}
},
methods: {
sendData() {
var data = [
{
Input1: this.input1,
Input2: this.input2
},
]
this.$emit("saveClick", data); //Event is "saveClick" event.
},
},
beforeMount(){
//Make a local copy
this.input1 = this.childData[0].Input1;
this.input2 = this.childData[0].Input2;
}
}
</script>

Redraw vue component on fetch update

When on button click I want to refresh list of items.
Button is trigger on a sibling component.
Watch method only gets called once. But I need a constant refresh
Parent element.
<template>
<div class="container">
<Filter #changedKeywords="reloadItems"></Filter>
<List :platforms="platforms" :filters="keywords"></List>
</div>
</template>
<script>
imports...
export default {
name: "Holder",
components: {Filter, List},
methods: {
reloadItems: function (data){
if(data.keywords) {this.keywords = data.keywords};
}
},
data(){
return {
keywords : null,
}
}
}
</script>
I want to redraw child this element multiple times, on each (filter)button click
<template>
<section class="list">
<div class="container">
<div class="holder">
<Game v-for="data in list" :key="data.id" :data="data" />
</div>
</div>
</section>
</template>
<script>
import Game from "./Game";
export default {
name: "List",
props: ['filters', 'platforms'],
components: {Game},
data() {
return{
list: [],
}
},
watch: {
filters: async function() {
console.log('gets called only once!!!'); // this is where I want to fetch new items
const res = await fetch('/api/game/list/9', {
method: 'POST',
body: JSON.stringify({'filters' : this.filters})
});
this.list = await res.json();
}
},
}
</script>

When you're watching objects and arrays you need to use a deep watcher.
The Solution
watch: {
filter: {
deep: true,
async handler(next, previous) {
//your code here
}
}
}
The Reason
Javascript primitives are stored by value, but Objects (including Arrays which are a special kind of Object) are stored by reference. Changing the contents of an Object doesn't change the reference, and the reference is what is being watched. Going from null to some object reference is an observable change, but subsequent changes aren't. When you use a deep watcher it will detect nested changes.

Vue.js : Passing Props Down to Child Components to Update Styles in the DOM

I'm a beginner trying to get my app to pass props that set CSS styles down a chain to child components. I have a listener that checks for view port size, and as the window gets resized, it checks past a certain point and then swaps the css class and passes it down the chain..
I think I may be doing something incorrectly because my child components don't seem to be receiving the new styles and aren't updating in the DOM as I drag the window.
Here is my code.. I removed irrelevant code to make it easier to read:
Page_Listings.vue
<template>
<main>
<section>
<ListingRack
:prp_classes="rackClass"
/>
</section>
</main>
</template>
<script>
import ListingRack from './Listing__Rack.vue';
export default {
name: 'Front_Page__Panel',
data() {
return {
viewportWidth: window.innerWidth
}
},
methods: {},
mounted() { window.onresize = () => this.viewportWidth = window.innerWidth },
components: {ListingRack},
},
computed: {
rackClass: function(){
let theValue;
console.log('>> viewport width is now: ',this.viewportWidth)
if(this.viewportWidth > 1200) {
theValue = "grid_view";
console.log('>> grid view')
}
else {
theValue = 'card_view';
console.log('>> card view')
}
return theValue
}
}
}
</script>
Listing__Rack.vue
<template>
<div class="listing_rack" :class="classes">
<ul>
<li v-for="item in listings" :key="item.postId">
// I removed irrelevant code for hte sake of simplicity in this example.
// listings is a GraphQL returned array of data that generates a list of "listings".
<Listing
:prp_classes=classes
/>
</li>
</ul>
</div>
</template>
<script>
import Listing from './Listing.vue'
export default {
name: 'listing__rack',
data() {
return {
posts: [], // what we get from the database.
listings: [], // what we copy from the database.
classes: this.prp_classes
}
},
props: {
prp_classes: String
},
components: {
Listing
},
watch: {
classes: function(){
//just to check if we're receiving anything...
console.log(">> [Listing_Rack](watch)(classes) there was a change to classes!");
}
}
}
</script>
Listing.vue
<template>
<div :id=id
:class=classes
class="listing"
:style="backgroundStyle"
>
</div>
</template>
<script>
export default {
name: 'Listing',
data() {
return {
classes: this.prp_classes,
backgroundStyle: String
}
},
props: {
prp_classes: String
},
methods: {
checkClasses: function(){
if(this.classes === 'grid_view') this.backgroundStyle = 'background: center / cover no-repeat url(background.jpg);';
}
},
mounted: function() {
this.checkClasses();
},
watch: {
classes: function(){
this.checkClasses();
}
}
}
</script>
My console.logs on rackClass so I know the class swapping part is working, but all my subsequent child components don't seem to be updating accordingly..
Can someone tell me what I'm doing wrong? Is there a better way to do this? How come my props aren't being passed when I drag the window, and how can I dynamically set styles in the DOM?

Your code does not work because of the one big mistake (don't worry, many people do it)
You are passing your classes using props to child components. But instead of using this prop (prp_classes) directly in the child's template, you create an absolutely unnecessary classes property in the data()
Problem with that is that data() is executed only once when the component is created. If the value of the prp_classes prop changes later, classes property from the data() just holds the old value.
To fix this, remove unnecessary classes from the data and use the prop directly in the template...
...bit more explanation by example what is going on:
let prp_classes = 'card_view'
let classes = prp_classes
prp_classes = 'grid_view'
// prp_classes === 'grid_view', classes === 'card_view', prp_classes !== classes
// strings/numbers/Date ...all work the same
let o1 = { a: 1 }
let o2 = o1
o1.a = 2
// o1.a === 2, o2.a === 2, o1 === o2
More to study

Make a reactive component with vuejs

I need a Vue component to show some HTML content in v-data-table from Vuetify. I have seen this post Vue 2 contentEditable with v-model, and I created a similar code shown below.
My problem is the component is not reactive. When I click the "Test button", no content is updated in HtmlTextArea.
<template>
<div>
<v-btn #click="doTest()">Test Button</v-btn>
<HtmlTextArea
v-model="content"
style="max-height:50px;overflow-y: scroll;"
></HtmlTextArea>
</div>
<template>
export default {
name: "ModelosAtestados",
components: { HtmlTextArea },
data: () => ({
content: "",
}),
methods: {
doTest() {
this.content = "kjsadlkjkasfdkjdsjkl";
},
},
};
//component
<template>
<div ref="editable" contenteditable="false" v-on="listeners"></div>
</template>
<script>
export default {
name: "HtmlTextArea",
props: {
value: {
type: String,
default: "",
},
},
computed: {
listeners() {
return { ...this.$listeners, input: this.onInput };
},
},
mounted() {
this.$refs.editable.innerHTML = this.value;
},
methods: {
onInput(e) {
this.$emit("input", e.target.innerHTML);
},
},
};
</script>

This occurs because HtmlTextArea sets the div contents to its value prop only in the mounted lifecycle hook, which is not reactive.
The fix is to setup a watcher on value, so that the div contents are updated to match whenever a change occurs:
// HtmlTextArea.vue
export default {
watch: {
value: {
handler(value) {
this.$refs.editable.innerHTML = value;
}
}
}
}
demo

In the #click event binder, you have to pass a function. You passed the result of an executed function.
To make it work: #click="doTest" or #click="() => doTest()".
How to debug such problems:
Display the value you want to update on your template to check if its updated: {{content}}
Use the vue devtool extension to check the current state of your components

Update a template after state changes using non-vuex state management

I am making an app which increments a value when you click a + button.
I am following the example from the documentation on Simple State Management.
I have set up an event handling method which increments a state value. This is triggered when a button is clicked. It updates the state value, but the template doesn't update.
To prove this, I have set up console logs in my increment function that fire and reflect the state value as expected. However, the value in the DOM never changes:
I have tried referring to the counterValue in the template as state.counterValue and store.state.counterValue but I get console errors for this.
What am I doing wrong?
Here is my template:
<template>
<div>
<h1>{{store.state.counterValue}}</h1>
<button v-on:click="increment">+</button>
</div>
</template>
Here is my script:
<script>
const store = {
debug: true,
state: {
counterValue: 0
},
increment() {
console.log('updating counterValue...')
this.state.counterValue = this.state.counterValue + 1
console.log(this.state.counterValue)
}
}
export default {
data() {
return {
counterValue: store.state.counterValue
}
},
methods: {
increment: function() {
store.increment()
}
}
}
</script>

The Problem With {{store.state.counterValue}}
From the docs
The mustache tag will be replaced with the value of the msg property on the corresponding data object.
Your data object (i.e. the component/vue-instance) does not have a property named store. To access const store, you need to proxy it through the component:
data() {
return {
store: store
}
},
The Problem With counterValue: store.state.counterValue
This sets this.counterValue equal to the initial value of store.state.counterValue. But there is no code keeping them in sync. So, when store.state.counterValue changes, counterValue will remain the same.
Solution
Proxy const store through the component as explained above. Example:
const store = {
debug: true,
state: {
counterValue: 0
},
increment() {
console.log('updating counterValue...')
this.state.counterValue = this.state.counterValue + 1
console.log(this.state.counterValue)
}
}
new Vue({
el: '#app',
data() {
return {
store: store
}
},
methods: {
increment: function() {
this.store.increment();
}
}
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.1.4/vue.js"></script>
<div id="app">
<h1>{{store.state.counterValue}}</h1>
<button v-on:click="increment">+</button>
</div>