i would to create a web component with vue3 for manage inputs and forms.
But i have problem with two data binding.
I define the web component in my html page.
<vue-input-text id="prova_di_un_input_text" name="prova_di_un_input_text" value=''></vue-input-text>
and i hook the emit when i write
document.querySelector('#prova_di_un_input_text').addEventListener('update:value', function (e) {
console.log("input cambiato", e, e.detail)
let valore_da_aggiornare = e.detail[0].value
});
but i don't understand how can update web component value after get new value.
thanks for every support
You don't need to implement two-way data bindings in Vue (awesome, right?) yourself unless you need something specific. Just use v-model directive, here's the doc
Code example:
<vue-input-text v-model="myValue" id="prova_di_un_input_text" name="prova_di_un_input_text" />
const myValue = ref('')
Related
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 a custom directive for checking user roles for some component will be shown or not.
Vue.directive("permission", {
bind(el, binding) {
Vue.nextTick(() => {
el.vFillMarkerNode = document.createComment('');
el.parentNode.insertBefore(el.vFillMarkerNode, el.nextSibling);
if (Auth.canSee(binding.value)) {
el.textContent = binding.value;
} else {
el.parentNode.removeChild(el);
}
});
},
This will work but in the component which is not shown, It will get the data from api (on component created hook) even user does not have permission.
<mycomp v-permission="['Admin']"></mycomp>
Is there any way to tell the vue, if my directive condition does not fit, do not fire related component 'created' hook, so do not get data from api?
I don't think this is the right way to do what you are trying to do. Since you are depending on the root-element on the component in order to do your checks. You are doing your checks after the component has already mounted. hence the Vue.nexTick().
There are a two ways you could solve this issue.
Run your logic in the Vuex Store and use mapGetters in the parent component to get the permissions in all of your components.
Bind your permissions to the root element and do v-if="$root.permissions.includes('admin')" on your component
Following this tutorial, I'm trying to programmatically create instances of a component on my page.
The main snippet is this:
import Button from 'Button.vue'
import Vue from 'vue'
var ComponentClass = Vue.extend(Button)
var instance = new ComponentClass()
instance.$mount()
this.$refs.container.appendChild(instance.$el)
However I get two errors:
The component I'm trying to instantiate contains references to the store, and these don't work: "TypeError: Cannot read property 'state' of undefined".
For the last line of the snippet (this.$refs.container.appendChild(instance.$el)) I get this error: "Uncaught TypeError: Cannot read property 'container' of undefined"
I'm really not sure how to troubleshoot this, if anyone strong in Vue.js could give me some hint as to why I'm getting these errors and to solve them that would be terrific.
1) Since you're manually instantiating that component and it doesn't belong to your main app's component tree, the store won't be automatically injected into it from your root component. You'll have to manually provide the store to the constructor when you instantiate the component ..
import ProjectRow from "./ProjectRow.vue";
import Vue from "vue";
import store from "../store";
let ProjectRowClass = Vue.extend(ProjectRow);
let ProjectRowInstance = new ProjectRowClass({ store });
2) In a Vue Single File Component (SFC), outside of the default export this doesn't refer to the Vue instance, so you don't have access to $refs or any other Vue instance property/method. To gain access to the Vue instance you'll need to move this line this.$refs.container.appendChild(instance.$el) somewhere inside the default export, for example in the mounted hook or inside one of your methods.
See this CodeSandbox for an example of how you may go about this.
This is another way to instantiate a component in Vue.js, you can use two different root elements.
// Instantiate you main app
var app = new Vue({
el: '#app',
data: {
message: 'Hello Vue!'
}
})
//
// Then instantiate your component dynamically
//
// Create a component or import it.
const Hello = {
props: ['text'],
template: '<div class="hello">{{ text }}</div>',
};
// Create a componentClass by Vue.
const HelloCtor = Vue.extend(Hello);
// Use componentClass to instantiate your component.
const vm = new HelloCtor({
propsData: {
text: 'HI :)'
}
})
// then mount it to an element.
.$mount('#mount');
It works by assigning "this" to the property "parent". By setting the parent you also have access to the $store in the new instance. (Provided that "this" is another Vue instance/Component and already has access to the store, of course)
new (Vue.extend(YourNewComponent))({
parent: this,
propsData: {
whatever: 'some value',
},
}).$mount(el.querySelector('.some-id'))
If you don't need the reference to the parent, you can just leave "parent: this," out.
Important note: When mounting many (like 500+) items on the page this way you will get a huge performance hit. It is better to only give the new Component the necessary stuff via props instead of giving it the entire "this" object.
I went down this path, following all the examples above, and even this one: https://css-tricks.com/creating-vue-js-component-instances-programmatically/
While I got far, and it works (I made a lot of components this way), at least for my case, it came with drawbacks. For example I'm using Vuetify at the same time, and the dynamically added components didn't belong to the outer form, which meant that while local (per component) validation worked, the form didn't receive the overall status. Another thing that did not work was to disable the form. With more work, passing the form as parent property, some of that got working, but what about removing components. That didn't go well. While they were invisible, they were not really removed (memory leak).
So I changed to use render functions. It is actually much easier, well documented (both Vue 2 and Vue 3), and everything just works. I also had good help from this project: https://koumoul-dev.github.io/vuetify-jsonschema-form/latest/
Basically, to add a function dynamically, just implement the render() function instead of using a template. Works a bit like React. You can implement any logic in here to choose the tag, the options, everything. Just return that, and Vue will build the shadow-DOM and keep the real DOM up to date.
The methods in here seems to manipulate the DOM directly, which I'm glad I no longer have to do.
I'm using the vue-cli scaffold for webpack
My Vue component structure/heirarchy currently looks like the following:
App
PDF Template
Background
Dynamic Template Image
Static Template Image
Markdown
At the app level, I want a vuejs component method that can aggregate all of the child component's data into a single JSON object that can be sent off to the server.
Is there a way to access child component's data? Specifically, multiple layers deep?
If not, what is the best practice for passing down oberservable data/parameters, so that when it's modified by child components I have access to the new values? I'm trying to avoid hard dependencies between components, so as of right now, the only thing passed using component attributes are initialization values.
UPDATE:
Solid answers. Resources I found helpful after reviewing both answers:
Vuex and when to use it
Vuex alternative solution for smaller apps
In my child component, there are no buttons to emit changed data. It's a form with somewhat 5~10 inputs. the data will be submitted once you click the process button in another component. so, I can't emit every property when it's changing.
So, what I did,
In my parent component, I can access child's data from "ref"
e.g
<markdown ref="markdowndetails"></markdown>
<app-button #submit="process"></app-button>
// js
methods:{
process: function(){
// items is defined object inside data()
var markdowns = this.$refs.markdowndetails.items
}
}
Note: If you do this all over the application I suggest move to vuex instead.
For this kind of structure It's good to have some kind of Store.
VueJS provide solution for that, and It's called Vuex.If you are not ready to go with Vuex, you can create your own simple store.
Let's try with this
MarkdownStore.js
export default {
data: {
items: []
},
// Methods that you need, for e.g fetching data from server etc.
fetchData() {
// fetch logic
}
}
And now you can use those data everywhere, with importing this Store file
HomeView.vue
import MarkdownStore from '../stores/MarkdownStore'
export default {
data() {
sharedItems: MarkdownStore.data
},
created() {
MarkdownStore.fetchData()
}
}
So that's the basic flow that you could use, If you dont' want to go with Vuex.
what is the best practice for passing down oberservable data/parameters, so that when it's modified by child components I have access to the new values?
The flow of props is one way down, a child should never modify its props directly.
For a complex application, vuex is the solution, but for a simple case vuex is an overkill. Just like what #Belmin said, you can even use a plain JavaScript object for that, thanks to the reactivity system.
Another solution is using events. Vue has already implemented the EventEmitter interface, a child can use this.$emit('eventName', data) to communicate with its parent.
The parent will listen on the event like this: (#update is the shorthand of v-on:update)
<child :value="value" #update="onChildUpdate" />
and update the data in the event handler:
methods: {
onChildUpdate (newValue) {
this.value = newValue
}
}
Here is a simple example of custom events in Vue:
http://codepen.io/CodinCat/pen/ZBELjm?editors=1010
This is just parent-child communication, if a component needs to talk to its siblings, then you will need a global event bus, in Vue.js, you can just use an empty Vue instance:
const bus = new Vue()
// In component A
bus.$on('somethingUpdated', data => { ... })
// In component B
bus.$emit('somethingUpdated', newData)
you can meke ref to child component and use it as this
this.$refs.refComponentName.$data
parent-component
<template>
<section>
<childComponent ref="nameOfRef" />
</section>
</template>
methods: {
save() {
let Data = this.$refs.nameOfRef.$data;
}
},
In my case I have a registration form that I've broken down into components.
As suggested above I used $refs, In my parent I have for example:
In Template:
<Personal ref="personal" />
Script - Parent Component
export default {
components: {
Personal,
Employment
},
data() {
return {
personal: null,
education: null
}
},
mounted: function(){
this.personal = this.$refs.personal.model
this.education = this.$refs.education.model
}
}
This works well as the data is reactive.
I have a vue.js app where I use the componenttag with :is="currentView" approach for changing the active view. I have a "state machine" that keeps track of valid transitions from a component to another component depending on some business logic. Sometimes this will tell the vue instance that the new value of currentViewis the same as the old one. If this happens, the component will not be reloaded. Is there any way I can force the component to reload even if the view is the same? That is I want the data to be reloaded, and the lifecycle hooks being executed.
You can add a unique key attribute to your component definition so that it correctly triggers all the component lifecycle methods.
Your component definition should look something like this:
<component :is="view" :key="unique_key"></component>
Helpful links:
Reloading a dynamic component
Vue 'key' api reference
This seems to do the trick, hower it causes the view to flash, is there a way I can avoid this?
const oldView = this.currentView
this.currentView = engine.advance()
if(this.currentView == oldView) {
//force reload!
this.currentView = ''
this.$nextTick(function () {
this.currentView = oldView
})
}