Vue newbie here.
Reading the following guide on view components:
https://v2.vuejs.org/v2/guide/components-custom-events.html#Customizing-Component-v-model
Presumably upon clicking the checkbox, the value of 'lovingVue' will be passed to the 'checked' prop which will either be a true or false value. But I don't understand what the Vue instance should look like and am wondering if someone can explain this to me?
Cheers,
Geof.
JS Fiddle Demo (open your console when you are using it)
Hey geofrey,
First of all, I think that I am newbie too and i will always be :)....
Vue.component() is a way of making component templets but inside the script not inside the HTML templet....still you need to initiate a new Vue() instance.
the "$emit('change', $event.target.checked) inside the child a component, is just a way for the Child component to send back values to the Parent component...
the first argument the $emit() takes is the event listener name (can be any word), check this link , so that's why the event listener here <base-checkbox #change="lovingVue"> is called #change.
The second argument it takes is which value you want to send back to the parent...in this case we want to send the v-bind:checked="checked" value....and this name is what we mention after the $event.target.
then comes the lovingVue part which you can call it as a function in the methods (as if you were treating it as any other event), and it will be carrying the value with it
new Vue({
//'#app' is the name of the parent componenet
el: '#app',
methods:{
// The e (can be any letter or word) here is the value that was emitted by the
// child(base-checkbox) to the parent(app)...and this case the value is Boolean
lovingVue(e){
console.log(e)
}
}
})
Related
I have a page with a component and the page needs to access a variable in that component. Would be nice if it were reactive. Then from the page I need to activate a function in the component. Would be nice if it could be done without a reactive variable. My question is 1: what's the best way to activate the function from the parent, for example when I click a button and 2: it seems very unintuitive and random to me that they aren't both possible in both directions? Anyone maybe know how Vue suggest you do it? This whole thing seems so complex relative to the relatively simple thing I'm trying to do.
I guess I try to use props? Or are refs a better option here?
So in general: you use refs, if you need the dom element, that's the whole purpose of refs. Since you don't mention that you n ed the dom element, you don't need to use that here.
There are 3 ways of communication: parent to child via props: https://vuejs.org/guide/components/props.html
child to parent via events
https://vuejs.org/guide/components/events.html
and anyone to anyone via event bus, which need an extra lib in vue3 and is out of scope for your question
https://v3-migration.vuejs.org/breaking-changes/events-api.html#event-bus
If you want to execute a function in the component whenever the value changes, you can put a watcher on the prop.
The other way around, from child to parent, you just create a listener to your emitted event and invoke a function of your choice. There are good examples in the docs in my opinion.
As per my understanding, You want to trigger the child component method from the Parent component without passing any prop as a input parameter and in same way you want to access child component data in the parent component without $emit. If Yes, You can simply achieve this using $refs.
You can attach the ref to the child component and then access it's variables and methods with the help of this $refs.
Live Demo (Just for a demo purpose I am using Vue 2, You can make the changes as per Vue 3) :
Vue.component('child', {
data: {
childVar: ''
},
methods: {
triggerEventInChildFromParent() {
console.log('Child Function triggered from Parent');
}
},
mounted() {
this.childVar = 'Child component variable'
}
});
var app = new Vue({
el: '#app',
methods: {
triggerEventInChild() {
this.$refs.child.triggerEventInChildFromParent()
}
},
mounted() {
console.log(this.$refs.child.childVar)
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
<div id="app">
<button #click="triggerEventInChild">
Button in Parent
</button>
<child ref="child"></child>
</div>
I am having a problem working with JQuery DataTable. I had to use that plugin since I had no other choice allowed due to my project requirements.
So the problem is that, I am adding rows to DataTable and in the row there's a column with button HTML tag. Now I want to bind an on click handler to the button.
dt.Rows.Add({
column_1_data,
column_2_data,
"<button #click='itsVueTime'>MyButton</button>"
});
Here dt is the DataTable's instance. Now the problem is #click won't work. I understand that its not being rendered by Vue thats why its not working.
Is there a way to bind click event in this condition?
Without knowing more context, I would recommend this way of doing it
In your component with the method you want to use, you can expose the component like this. (I use mounted, but you can use other lifecycle methods too like created)
mounted() {
window.app = this;
}
then you can use
<button onclick="app.holler()">Say Hello</button>
you can also expose just the function you want to use like so
mounted() {
window.itsVueTime = this.itsVueTime;
}
I have two components in mu app.vue and i will send data from app.vue to my first component(filter component) at the time of page load.
Now based on the user actions in the displayed data in the second component i need to pass new vales back to the first component.
There i am using a and a . Consider one of the props i receive in the first component is "nselectedOption" and i do this in data: { return { selectedOption: this.nselectedOption }} to avoid mutation warning.
Now everytime i update the values for this component from second component, i am seeing changes in "nselectedOption" only and not in "selectedOption". Can you explain why is that ?
I need the updated value into a v-model of .
1. If i use "nselectedOption" it is updating the textbox but while editing the value throws error.
2. If i use "selectedOption" it is not updating the values in the textbox itself.
I have even tried using the computed values to return the value, it works but if i try to change values in other options in the filter component the already updated values displays null or nothing.
Please help me. Is this problem can be solved using State Management Concept or do i have to have a separate compoenent other than App.Vue to do all this so that it would act as a parent/child kinda thing or is there anyother way to overcome this.
Try using watcher. If you watch for nselectedOption, everytime it changes, the watcher will fire and bind the changed value to selectedOption.
props: ['nselectedOption'],
data: {
selectedOption
},
watch: {
nselectedOption: function (val) {
this.selectedOption = val
}
}
Also, if the prop you are watching is an object/array, consider using spread operator if you want to make a local copy to avoid mutation.
this.someObj = { ...someProp }
I have a problem with accessing data from the component using slots.
Here's my code:
codepen.io/anon/pen/BbOEZz
I want the line:
<p slot="desc">{{ desc_01 }}</p>
It started working and at the slot in the template displayed the value with date.
Can anyone help me with this matter?
There are a couple of mistakes in your code
1.You don't access data directly from the child. The child communicates with the parent via events, using emit.
You should
fire an event from the child
listen to the event on the parent
update a variable on the parent.
2.There is no desc_01 declared on the app. The template is executed in the context of the app and not the child, so you also need to define that property.
data () {
return {
desc_01: ''
}
}
I've added a code pen for this here.
I'm doing a project with ElementUI Tabs (just HTML and JS files, no .vue files) and I want to open a new Tab, and add html inside, like I've always used to do in Jquery and SemanticUI, for example, the user clicks the menu called "Person" and the Person View (a Vue component) opens in the tab (id = "tab1") to add a new person register, and if the user clicks again the "Person" menu, another tab opens (id = "tab2") with the Person View.
First Question: Because the Vue Component has no "el:" selector, how can I tell to component (Person View) to open inside the "tab1", and another click to open inside the "tab2" ? There is any selector like "el" in Vue.component()?
Second Question: Using Vue instance ( new Vue ({options}) ), it works, because is possible to use the selector "el", but I've read before in some blogs, that is not good practice, because the app must have only one instance of Vue. Is correct add more than one Vue instance ( new Vue () ) as used to be done adding many Vue.component ({}) in the project?
Third Question: I've read before that Vue.component() is a Vue instance, and so would be correct to say that Vue.component() and Vue() is the same thing, but with different sintax ?
Question 1:
Actually, a component does have an el. Your template determines what el is.
For example, I created an inline template for my select2 that look like this:
<select2>
<select></select>
</select2>
Vue.componet("select2", {blah blah blah});
in this case el is the select box directly.
If I did:
<select2>
<div>
<select></select>
</div>
</select2>
the component el would be the div.
Question 2: what you heard from those blogs is nonsense, at least as far as Vue 2 is concerned (never worked with ver 1)
You, as a coder, determine what el is in your code so it is safe to use as a selector. I do it all of the time.
Vues cannot overlap but you can have as many on a page as makes sense. On one set of my tabs, each tab is completely different from each other and independent of each other so each has its own Vue instance. On another, each tab is the same so a made a single component and generated it inside each tab as part of the parent Vue instance.
question 3:
Think of Components as parts and the Vue instance as the whole containing the parts. I personally use components to reduce and compartmentalize code. For example, I have a DataTables component, a select2 component and a tab component, in all cases I have a number of each on each page. Then all I need to do is include them in my Vue instance definition.
After almost two weeks trying, I got it !
First i created an object that has a component structure in a JS file
(personview.js) that i load with requireJS, and pass as a parameter to a
method of Vue Instance called appVue:
appVue.addComponent(componentName,{name:"personview",template:"<div>html tags...</div>",methods:...});
In appVue i added the method:
var appVue=new Vue({
el:'#app',
data() {
return {
components: {},
instances: {}
}
},
methods: {
addComponent(componentName,componentBody){
this.$data.components[componentName]=Vue.component(componentName,Vue.extend(componentBody));
}
}
}
When the user clicks on menu, the method openViewByClickOnMenu is called
and executes:
methods: {
openViewByClickOnMenu(){
//id to identify the components and scripts to load
var componentName="personView"; //for this example i forced the name
//call a method that adds the new tab, and inside the tab adds
//<div id="divX"></div> and return the counter ever increased.
//X in id attribute is the number genereate by the counter
var ctTab=body.addTab({label:menuItem.label});
// will be used to identify an instance of compoment
var componentId=componentName+ctTab; //will be personView1, personView2, etc..
// will be used to identify the div where i want to show component
var divTabId="div"+ctTab;
//load the personview.js with component body
requirejs([componentName],function(){
//creates a new instance of component
app.$data.instances[componentId]=new app.$data.componentes[componentName];
//mounts the component in the div that i want
app.$data.instances[componentId].$mount("#"+divTabId);
});
}
I think the Vue team could add a method in Vue instance to add
components dinamically more easily, sometimes there's no need to
load all html and js files because the user has no acess/permissions
to see some views. And i miss a way to load html native, like
Angular does, because sometimes we need generate html from template engine
inside a SpringBoot for example.