I am terribly new to Vue, so forgive me if my terminology is off. I have a .NET Core MVC project with small, separate vue pages. On my current page, I return a view from the controller that just has:
#model long;
<div id="faq-category" v-bind:faqCategoryId="#Model"></div>
#section Scripts {
<script src="~/scripts/js/faqCategory.js"></script>
}
Where I send in the id of the item this page will go grab and create the edit form for. faqCategory.js is the compiled vue app. I need to pass in the long parameter to the vue app on initialization, so it can go fetch the full object. I mount it with a main.ts like:
import { createApp } from 'vue'
import FaqCategoryPage from './FaqCategoryPage.vue'
createApp(FaqCategoryPage)
.mount('#faq-category');
How can I get my faqCategoryId into my vue app to kick off the initialization and load the object? My v-bind attempt seems to not work - I have a #Prop(Number) readonly faqCategoryId: number = 0; on the vue component, but it is always 0.
My FaqCategoryPAge.vue script is simply:
<script lang="ts">
import { Options, Vue } from "vue-class-component";
import { Prop } from 'vue-property-decorator'
import Card from "#/Card.vue";
import axios from "axios";
import FaqCategory from "../shared/FaqCategory";
#Options({
components: {
Card,
},
})
export default class FaqCategoryPage extends Vue {
#Prop(Number) readonly faqCategoryId: number = 0;
mounted() {
console.log(this.faqCategoryId);
}
}
</script>
It seems passing props to root instance vie attributes placed on element the app is mounting on is not supported
You can solve it using data- attributes easily
Vue 2
const mountEl = document.querySelector("#app");
new Vue({
propsData: { ...mountEl.dataset },
props: ["message"]
}).$mount("#app");
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
<div id="app" data-message="Hello from HTML">
{{ message }}
</div>
Vue 3
const mountEl = document.querySelector("#app");
Vue.createApp({
props: ["message"]
}, { ...mountEl.dataset }).mount("#app");
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/3.0.0/vue.global.js"></script>
<div id="app" data-message="Hello from HTML">
{{ message }}
</div>
Biggest disadvantage of this is that everything taken from data- attributes is a string so if your component expects something else (Number, Boolean etc) you need to make conversion yourself.
One more option of course is pushing your component one level down. As long as you use v-bind (:counter), proper JS type is passed into the component:
Vue.createApp({
components: {
MyComponent: {
props: {
message: String,
counter: Number
},
template: '<div> {{ message }} (counter: {{ counter }}) </div>'
}
},
}).mount("#app");
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/3.0.0/vue.global.js"></script>
<div id="app">
<my-component :message="'Hello from HTML'" :counter="10" />
</div>
Just an idea (not a real problem)
Not really sure but it can be a problem with Props casing
HTML attribute names are case-insensitive, so browsers will interpret any uppercase characters as lowercase. That means when you're using in-DOM templates, camelCased prop names need to use their kebab-cased (hyphen-delimited) equivalents
Try to change your MVC view into this:
<div id="faq-category" v-bind:faq-category-id="#Model"></div>
Further to Michal Levý's answer regarding Vue 3, you can also implement that pattern with a Single File Component:
app.html
<div id="app" data-message="My Message"/>
app.js
import { createApp } from 'vue';
import MyComponent from './my-component.vue';
const mountEl = document.querySelector("#app");
Vue.createApp(MyComponent, { ...mountEl.dataset }).mount("#app");
my-component.vue
<template>
{{ message }}
</template>
<script>
export default {
props: {
message: String
}
};
</script>
Or you could even grab data from anywhere on the parent HTML page, eg:
app.html
<h1>My Message</h1>
<div id="app"/>
app.js
import { createApp } from 'vue';
import MyComponent from './my-component.vue';
const message = document.querySelector('h1').innerText;
Vue.createApp(MyComponent, { message }).mount("#app");
my-component.vue
<template>
{{ message }}
</template>
<script>
export default {
props: {
message: String
}
};
</script>
To answer TheStoryCoder's question: you would need to use a data prop. My answers above demonstrate how to pass a value from the parent DOM to the Vue app when it is mounted. If you wanted to then change the value of message after it was mounted, you would need to do something like this (I've called the data prop myMessage for clarity, but you could also just use the same prop name message):
<template>
{{ myMessage }}
<button #click="myMessage = 'foo'">Foo me</button>
</template>
<script>
export default {
props: {
message: String
},
data() {
return {
myMessage: this.message
}
}
};
</script>
So I'm not at all familiar with .NET and what model does, but Vue will treat the DOM element as a placeholder only and it does not extend to it the same functionality as the components within the app have.
so v-bind is not going to work, even without the value being reactive, the option is not there to do it.
you could try a hack to access the value and assign to a data such as...
const app = Vue.createApp({
data(){
return {
faqCategoryId: null
}
},
mounted() {
const props = ["faqCategoryId"]
const el = this.$el.parentElement;
props.forEach((key) => {
const val = el.getAttribute(key);
if(val !== null) this[key] = (val);
})
}
})
app.mount('#app')
<script src="https://unpkg.com/vue#3.0.0-rc.11/dist/vue.global.prod.js"></script>
<div id="app" faqCategoryId="12">
<h1>Faq Category Id: {{faqCategoryId}}</h1>
</div>
where you get the value from the html dom element, and assign to a data. The reason I'm suggesting data instead of props is that props are setup to be write only, so you wouldn't be able to override them, so instead I've used a variable props to define the props to look for in the dom element.
Another option
is to use inject/provide
it's easier to just use js to provide the variable, but assuming you want to use this in an mvc framework, so that it is managed through the view only. In addition, you can make it simpler by picking the exact attributes you want to pass to the application, but this provides a better "framework" for reuse.
const mount = ($el) => {
const app = Vue.createApp({
inject: {
faqCategoryId: {
default: 'optional'
},
},
})
const el = document.querySelector($el)
Object.keys(app._component.inject).forEach(key => {
if (el.getAttribute(key) !== null) {
app.provide(key, el.getAttribute(key))
}
})
app.mount('#app')
}
mount('#app')
<script src="https://unpkg.com/vue#3.0.0-rc.11/dist/vue.global.prod.js"></script>
<div id="app" faqCategoryId="66">
<h1>Faq Category Id: {{faqCategoryId}}</h1>
</div>
As i tried in the following example
https://codepen.io/boussadjra/pen/vYGvXvq
you could do :
mounted() {
console.log(this.$el.parentElement.getAttribute("faqCategoryId"));
}
All other answers might be valid, but for Vue 3 the simple way is here:
import {createApp} from 'vue'
import rootComponent from './app.vue'
let rootProps = {};
createApp(rootComponent, rootProps)
.mount('#somewhere')
Related
I have the problem that my UI is somehow not updating after the applications fetches some data from the sever backend.
I have the following code:
<template>
<div v-if="restaurant">
<div class="center logo-container">
<img class="img-fit" v-bind:src="'/api/restaurant/logo/' + restaurant.id" alt=""/>
</div>
<h2 class="title center dm-text-header">{{ restaurant.name }}</h2>
<h4 class="subheading center">{{ restaurant.address.street }}, {{ restaurant.address.city }}</h4>
</div>
</template>
<script lang="ts">
import axios from 'axios';
import { Options, Vue } from "vue-class-component";
import { Tag } from "./Tag";
import { Restaurant } from "./Restaurant";
#Options({
props: {
}
})
export default class Menu extends Vue {
// hardcoded for testing
restaurantId = "8ykw9ljq";
tagUrl = "/api/menu/" + this.restaurantId + "/tags";
restaurantUrl = "/api/restaurant/" + this.restaurantId;
restaurant!: Restaurant;
tags: Tag[] = [];
mounted() {
// get tags
this.getTags();
// get restaurant
this.getRestaurant();
}
getRestaurant(): void {
axios.get<Restaurant>(this.restaurantUrl)
.then(res => {
this.restaurant = res.data;
});
}
getTags(): void {
axios.get(this.tagUrl)
.then(res => {
this.tags = res.data;
});
}
}
</script>
I verified that the backend actually serves the correct restaurant and logged the results after the axios call finishes. The problem is that the DOM is not updated. If I add the following to the the DOM is upadated:
<template>
...
<div>
{{tags}}
</div>
<template>
It seems to me that vue somehow only updated the DOM if it recognizes changes to the already initialized empty array but not the currently uninitialized restaurant object.
I further get a warning:
[Vue warn]: Property "restaurant" was accessed during render but is not defined on instance. on the v-if what I kind of find strange because that is the exact reason it is there. How do I need to initialize the restaurant, such that the update through axios is correctly recognized by vue?
Try a Typescript union with null:
restaurant: Restaurant | null = null;
From the Vue Class Component docs:
Note that if the initial value is undefined, the class property will not be reactive which means the changes for the properties will not be detected
and
To avoid this, you can use null value or use data hook instead:
import Vue from 'vue'
import Component from 'vue-class-component'
#Component
export default class HelloWorld extends Vue {
// `message` will be reactive with `null` value
message = null
// See Hooks section for details about `data` hook inside class.
data() {
return {
// `hello` will be reactive as it is declared via `data` hook.
hello: undefined
}
}
}
I am loading a Vue component from another Vue component and am passing a property to that component. I need to access this property in the regular javascript of that component, but cannot figure out how to do this.
The simplified parent component could look as follows:
<template>
<div>
<MenuEdit :menu-list="menuList"></MenuEdit>
</div>
</template>
<script>
import MenuEdit from '#/components/MenuEdit';
export default {
name: 'Admin',
data: function () {
return {
menuList: ["Item1","Item2","Item3","Item4"]
};
},
components: {
MenuEdit
}
}
</script>
<style scoped>
</style>
And the MenuEdit could look as follows:
<template>
<div>
{{ menuList }}
</div>
</template>
<script>
//console.log(this.menuList) // Does not work.
export default {
name: 'MenuEdit',
props: [
'menuList'
],
methods: {
testMenu: function() {
console.log(this.menuList) //This works fine
}
}
}
</script>
<style scoped>
</style>
EDIT
To add some context to the question, I am implementing sortablejs on Buefy using the following example: https://buefy.org/extensions/sortablejs
Instead of calling "vnode.context.$buefy.toast.open(Moved ${item} from row ${evt.oldIndex + 1} to ${evt.newIndex + 1})" at the end of the first const, I want to update the component (or better said, update the related Array).
In the example, the const are defined outside of the component, which is why I ended up with this question.
You cannot access the prop as that code (where your console.log is) runs before the component is mounted, before it's even declared really
If you want to access stuff when the component is first mounted, you can use the mounted lifecycle method
I have two components:
App.vue
Sidekick.vue
In my App.vue component, I have a property that I would like to access from Sidekick.vue
App.vue
<template>
<div id="app">
<p>{{ myData }}</p>
<div class="sidebar">
<router-view/> // our sidekick component is shown here
</div>
</div>
</template>
<script>
export default {
name: 'App',
data () {
return {
myData: 'is just this string'
}
}
}
</script>
Sidekick.vue
<template>
<div class="sidekick">
{{ myData }}
</div>
</template>
<script>
export default {
name: 'Sidekick'
}
</script>
I would like access to myData (which is declared in App.vue) from Sidekick.vue
I have tried importing App.vue from within Sidekick.vue by doing something like:
Sidekick.vue (incorrect attempt)
<script>
import App from '#/App'
export default {
name: 'Sidekick',
data () {
return {
myData: App.myData
}
}
}
</script>
I have read about props - but have only seen references to child / parent components. In my case, Sidekick.vue is shown in a div inside App.vue (not sure if this makes it a "child"). Do I need to give access of myData to <router-view/> somehow?
UPDATE: (to show relationship between App.vue and Sidekick.vue
index.js (router file)
import Vue from 'vue'
import Router from 'vue-router'
import Sidekick from '#/components/Sidekick',
import FakeComponent from '#/components/FakeComponent'
Vue.use(Router)
const router = new Router({
routes: [
{
path: '/',
redirect: '/fakecomponent'
},
{
path: '/sidekick',
name: 'Sidekick',
component: Sidekick
},
{
path: '/fakecomponent',
name: 'FakeComponent',
component: FakeComponent
}
]
})
export default router
Sidekick.vue gets rendered when we hit /sidekick
Just keep in mind, the rule of thumb is using props to pass data in a one-way flow
props down, events up.
https://v2.vuejs.org/v2/guide/components.html#Composing-Components
Quick solution:
Global event bus to post messages between your <App/> and <Sidekick/> components.
https://v2.vuejs.org/v2/guide/components.html#Non-Parent-Child-Communication
Long term solution:
Use a state management library like vuex to better encapsulates data in one place (a global store) and subscribe it from your components tree using import { mapState, mapMutations } from 'vuex'
When you have parent-child communication, the best and recommended
option is to use props and events. Read more in Vue docs
When want to have shared state between many components the best and
recommended way is to use Vuex.
If you want to use simple data sharing you can use Vue observable.
Simple example: Say that you have a game and you want the errors to be accessible by many components. (components can access it and manipulate it).
errors.js
import Vue from "vue";
export const errors = Vue.observable({ count: 0 });
Component1.vue
import { errors } from 'path-of-errors.js'
export default {
computed: {
errors () {
get () { return errors.count },
set (val) { errors.count = val }
}
}
}
In Component1 the errors.count is reactive. So if as a template you have:
<template>
<div>
Errors: {{ errors }}
<button #click="errors++">Increase</button>
</div>
</template>
While you click the Increase button, you will see the errors increasing.
As you might expect, when you import the errors.js in another component, then both components can participate on manipulating the errors.count.
Note: Even though you might use the Vue.observable API for simple data sharing you should be aware that this is a very powerful API. For example read Using Vue Observables as a State Store
App.vue:
<router-view pass_data='myData'/>
Sidekick.vue:
export default {
name: "Sidekick",
props: ["pass_data"],
created() {
alert("pass_data: "+this.pass_data)
}
}
If App.js(Parent) and Sidekick(Child)
App.js
in Template
In script
import Sidekick from './Sidekick.vue:
Sidekick.vue
props: ['myData']
now you can access myData anywhere in sidekick.
In template myData and
in scripts this.myData
I have two components:
App.vue
Sidekick.vue
In my App.vue component, I have a property that I would like to access from Sidekick.vue
App.vue
<template>
<div id="app">
<p>{{ myData }}</p>
<div class="sidebar">
<router-view/> // our sidekick component is shown here
</div>
</div>
</template>
<script>
export default {
name: 'App',
data () {
return {
myData: 'is just this string'
}
}
}
</script>
Sidekick.vue
<template>
<div class="sidekick">
{{ myData }}
</div>
</template>
<script>
export default {
name: 'Sidekick'
}
</script>
I would like access to myData (which is declared in App.vue) from Sidekick.vue
I have tried importing App.vue from within Sidekick.vue by doing something like:
Sidekick.vue (incorrect attempt)
<script>
import App from '#/App'
export default {
name: 'Sidekick',
data () {
return {
myData: App.myData
}
}
}
</script>
I have read about props - but have only seen references to child / parent components. In my case, Sidekick.vue is shown in a div inside App.vue (not sure if this makes it a "child"). Do I need to give access of myData to <router-view/> somehow?
UPDATE: (to show relationship between App.vue and Sidekick.vue
index.js (router file)
import Vue from 'vue'
import Router from 'vue-router'
import Sidekick from '#/components/Sidekick',
import FakeComponent from '#/components/FakeComponent'
Vue.use(Router)
const router = new Router({
routes: [
{
path: '/',
redirect: '/fakecomponent'
},
{
path: '/sidekick',
name: 'Sidekick',
component: Sidekick
},
{
path: '/fakecomponent',
name: 'FakeComponent',
component: FakeComponent
}
]
})
export default router
Sidekick.vue gets rendered when we hit /sidekick
Just keep in mind, the rule of thumb is using props to pass data in a one-way flow
props down, events up.
https://v2.vuejs.org/v2/guide/components.html#Composing-Components
Quick solution:
Global event bus to post messages between your <App/> and <Sidekick/> components.
https://v2.vuejs.org/v2/guide/components.html#Non-Parent-Child-Communication
Long term solution:
Use a state management library like vuex to better encapsulates data in one place (a global store) and subscribe it from your components tree using import { mapState, mapMutations } from 'vuex'
When you have parent-child communication, the best and recommended
option is to use props and events. Read more in Vue docs
When want to have shared state between many components the best and
recommended way is to use Vuex.
If you want to use simple data sharing you can use Vue observable.
Simple example: Say that you have a game and you want the errors to be accessible by many components. (components can access it and manipulate it).
errors.js
import Vue from "vue";
export const errors = Vue.observable({ count: 0 });
Component1.vue
import { errors } from 'path-of-errors.js'
export default {
computed: {
errors () {
get () { return errors.count },
set (val) { errors.count = val }
}
}
}
In Component1 the errors.count is reactive. So if as a template you have:
<template>
<div>
Errors: {{ errors }}
<button #click="errors++">Increase</button>
</div>
</template>
While you click the Increase button, you will see the errors increasing.
As you might expect, when you import the errors.js in another component, then both components can participate on manipulating the errors.count.
Note: Even though you might use the Vue.observable API for simple data sharing you should be aware that this is a very powerful API. For example read Using Vue Observables as a State Store
App.vue:
<router-view pass_data='myData'/>
Sidekick.vue:
export default {
name: "Sidekick",
props: ["pass_data"],
created() {
alert("pass_data: "+this.pass_data)
}
}
If App.js(Parent) and Sidekick(Child)
App.js
in Template
In script
import Sidekick from './Sidekick.vue:
Sidekick.vue
props: ['myData']
now you can access myData anywhere in sidekick.
In template myData and
in scripts this.myData
I would like to separate the business logic and the template of a component.
In React I would use the Container/Presentation pattern.
const Container = (props) => <Presentational ...props/>
But what is the equivalent with vue.js?
Say I have this all in one component (did not test this one, it just for example) :
<template>
<div id="app">
<div v-for="user in users">
{{user.name}}
</div>
</div>
</template>
<script>
Vue.component({
el: '#app',
props: {
filter: "foo"
},
data: {
users: [],
},
ready: function () {
this.$http.get('/path/to/end-point?filter='+this.props.filter)
.then(function (response) {
this.users = response.data
})
}
})
</script>
How I could extract a container with just the fetch logic?
I really don't see a need for a container component. Abstract your fetch code out into a vuex action and bind your store state within the component using computed properties.
You can extend any Vue component, which will allow you to override any methods from the parent. So, you can create a base component and then extend that:
const Base = Vue.component('base-comp', {
template: "#base",
data() {
return {
name: 'foo'
}
}
});
const Child = Base.extend({
data() {
return {
name: 'bar'
}
}
});
Vue.component('child-comp', Child)
You can check out the JSFiddle here: https://jsfiddle.net/tdgxdhz9/
If you are using single file components, then it's simply a case of importing the base component and extending it, which keeps the original template in tact:
import Base from './BaseComponent.vue'
Base.extend({
// Javascript code here
})
You can use vuex-connect to create container components like in React. Here an example of project : https://github.com/pocka/vue-container-component-example
What you are looking for is Vue Mixins.
You can write a mixins file which contains your business logic and import it into your Vue components.
Link:- https://v2.vuejs.org/v2/guide/mixins.html