How does linking a local img in VueJs work? - vue.js

I was wondering how linking an local img in vue works (dynamic).
So what I do now is get the static link which will always be the same, with this src="../../../../public/groenten.png".(which works)
What I want to do is, get the image link from the prop "image".
which when I console log that image prop, I get the exact same link as the static one, which is great but when I try to switch my src to: :src="this.image" then my image wont show anymore.
<template>
<router-link v-bind:to="{ name: 'categoryPage', params: { category: this.title } }" class="itemlink">
<div class="category-item">
<div class="category-item__top">
<img
:class="imageClassName"
src="../../../../public/groenten.png"
alt="category"
/>
</div>
<div class="category-item__bottom">
<h3 class="category-item__title">{{ title }}</h3>
</div>
</div>
</router-link>
</template>
<script>
import { defineComponent } from "vue";
export default defineComponent({
name: "CategoryItem",
props: {
title: String,
image: String,
},
computed: {
imageClassName() {
return `category-item__${this.title.toLowerCase()}`;
}
},
created() {
console.log(this.image);
}
});
</script>

As far as I know, webpack is collecting static assets at compilation time. Even if at runtime the prop value is the same as the hardcoded one, it did not exist during compilation and it was not imported.
In order to import assets at runtime you have to explicitly call the require() function (webpack does the same thing during compilation):
<img :src="imageUrl" />
props: {
image: String,
},
computed: {
imageUrl(){
return require(this.image)
}
}

Related

Access External Link router-link button

I'm wanting to pass an external URL to be accessed by a button in my application. However, I want to access this URL globally, but I'm not able to implement it. When running my implementation nothing works
global.js
export const baseAppUrl = 'http://localhost:8080'
Component.vue
<script>
import { baseAppUrl } from '#/global'
export default {
name: "app-header",
data: function () {
return {
baseAppUrl: baseAppUrl,
};
},
methods: {
},
};
</script>
<b-button size="sm" class="my-2 my-sm-0" :to="baseAppUrl">SINGUP</b-button>
The variable baseAppUrl in the global file seems to be loaded correctly.
The problem is another one: the button should be wrapped in the template tag like this:
<template>
<div>
<p>This is the base app URL: {{ baseAppUrl }}</p>
<b-button size="sm" class="my-2 my-sm-0" :to="baseAppUrl">SINGUP</b-button>
</div>
</template>
<script>
import { baseAppUrl } from '#/global'
export default {
name: "app-header",
data: function () {
return {
baseAppUrl: baseAppUrl,
};
},
methods: {
},
};
</script>
Plus make sure that the file global.js is placed in the right directory.

Why won't vue.js update the DOM?

Working my way learning about Vue. I chose it as the better alternative after looking at React, Angular and Svelte.
I have a simple example that its not working probably because I'm not getting/understanding the reactive behaviour of Vue.
Plain simple App:
<template>
<div id="app">
<app-header></app-header>
<router-view />
<app-footer></app-footer>
</div>
</template>
<script>
import Header from './components/Header.vue'
import Home from './components/Home.vue'
import Footer from './components/Footer.vue'
export default {
components: {
name: 'App',
'app-header': Header,
'app-footer': Footer
}
}
</script>
Where Home.vue and Footer.vue have plain HTML content on the template.
On Header.vue I have:
<template>
<div>
<h1>The Header</h1>
<nav>
<ul>
<li>Curr Player: {{ ethaccount }}</li>
<li>Prop owner: {{ propOwner }}</li>
</ul>
</nav>
<hr />
</div>
</template>
<script>
export default {
data() {
return {
ethaccount: 'N/A',
propOwner: 'N/A'
}
},
methods: {
update() {
var ethaccount = '0xAAAAAA123456789123456789123456789'
console.log('ETH Account: ' + ethaccount)
var propOwner = '0xPPPPPPPPPPP987654321987654321'
console.log('Prop Account: ' + propOwner)
}
},
mounted() {
this.update()
}
}
</script>
But I'm unable to get the header updated and unable to find what I'm doing wrong. Help.
If you need to read a little bit more about the reactivity of the datas in vuejs check this link : https://v2.vuejs.org/v2/guide/reactivity.html
If you need to access/change your data try to do it like that :
this.$data.ethaccount = 'foo';
this.$data.propOwner = 'bar';
For me the problem is taht you re-declare your variable locally by doing :
var ethaccount = "0xAA...";
By doing such you never change the value of the data you're accessing through your template.
Hope it will solve your problem.

Vuejs 2 Data Binding Failed

I don't understand why it's not working and this driving me crazy
<template>
<p>{{ greeting }}</p>
</template>
<script>
export default {
name: 'App',
data: function(){
return {
greeting: 'this is message'
}
}
}
</script>
Why {{ greeting }} not working ? It should be run the text. But I got this error
Errors compiling template:
Component template should contain exactly one root element. If you are using v-if on multiple elements, use v-else-if to chain them instead.
Can anyone help me with this ?
You should have a <div> with an id app inside your <template> tag
<template>
<div id="app">{{greeting}}</div>
</template>
<script>
export default {
name: "App",
data: function() {
return {
greeting: "this is message"
};
}
};
</script>

Prop passed to child component is undefined in created method

I am using Vue.js 2.
I have a problem with passing value to the child component as a prop. I am trying to pass card to card-component.
In card-component I can access the prop in the Card goes here {{card}} section.
However when I try to access it in created or mounted methods it's undefined.
Parent:
<template>
<div class="container">
<div class="row">
<div class="col-md-8 col-md-offset-2">
<card-component :card="place.card"></card-component>
</div>
</div>
</div>
</template>
<script>
import CostComponent from './CostComponent';
import CardComponent from './CardComponent';
export default {
components: {
CostComponent, CardComponent
},
props: ['id'],
data() {
return {
place: []
}
},
created() {
axios.get('/api/places/' + this.id)
.then(response => this.place = response.data);
}
}
</script>
Child:
<template>
<div class="container">
<div class="row">
<div class="col-md-8 col-md-offset-2">
<ul class="list-unstyled">
Card goes here {{card}}
</ul>
</div>
</div>
</div>
</template>
<script>
import CardItemComponent from './CardItemComponent';
export default {
components: {
CardItemComponent
},
props: ['card'],
created() {
console.log(this.card); // undefined
},
mounted() {
console.log(this.card); // undefined
},
}
</script>
I did a lot of googling but none of the solutions I found have fixed my issue.
This is purely a timing issue. Here's what happens...
Your parent component is created. At this time it has an empty array assigned to place (this is also a problem but I'll get to that later). An async request is started
Your parent component creates a CardComponent instance via its template
<card-component :card="place.card"></card-component>
at this stage, place is still an empty array, therefore place.card is undefined
3. The CardComponent created hook runs, logging undefined
4. The CardComponent is mounted and its mounted hook runs (same logging result as created)
5. Your parent component is mounted
6. At some point after this, the async request resolves and changes place from an empty array to an object, presumably with a card property.
7. The new card property is passed down into your CardComponent and it reactively updates the displayed {{ card }} value in its template.
If you want to catch when the card prop data changes, you can use the beforeUpdate hook
beforeUpdate () {
console.log(this.card)
}
Demo
Vue.component('CardComponent', {
template: '<pre>card = {{ card }}</pre>',
props: ['card'],
created () {
console.log('created:', this.card)
},
mounted () {
console.log('mounted:', this.card)
},
beforeUpdate () {
console.log('beforeUpdate:', this.card)
}
})
new Vue({
el: '#app',
data: {
place: {}
},
created () {
setTimeout(() => {
this.place = { card: 'Ace of Spades' }
}, 2000)
}
})
<script src="https://cdn.jsdelivr.net/npm/vue"></script>
<div id="app">
<card-component :card="place.card" />
</div>
See https://v2.vuejs.org/v2/guide/instance.html#Lifecycle-Diagram
If place is meant to be an object, you should not be initialising it as an array. Also, if your CardComponent relies on data being present, you may want to conditionally render it.
For example
data () {
return { place: null }
}
and
<card-component v-if="place" :card="place.card"></card-component>
then CardComponent will only be created and mounted after place has data.
Make sure you have props: true in the router file. It is a simple solution but many of us forget this.
{
path: '/path-to',
name: 'Name To',
component: Component,
props: true
}

Why is the activated lifecycle hook not called on first visit

I have a problem where a component within a router-view that is being kept alive does not call its activated lifecycle hook when first created. The created and mounted lifecycle hooks are being called. On a second visit, the activated hook is being called.
The scenario is quite complicated as there is a bit of nesting and slot using involved.
I've tried to create a minimal example which you can find below, or a bit more detailed on https://codesandbox.io/s/251k1pq9n.
Unfortunately, it is quite large and still not as complicated as the real code which I unfortunately cannot share.
Worse, I failed to reproduce the actual problem in my minimal example. Here, the created, mounted, and activated lifecycle hooks are all called when first visiting SlotExample.
In my real code, only the created and mounted, lifecycle hooks are called on the first visit, the activated hook is called on subsequent visits. Interestingly, all lifecycle hooks are called as expected for SlotParent.
The real code involves more nesting and makes use of slots to use layout components.
My code is using Vue 2.5.16 and Vue-Router 3.0.1 but it also doesn't work as expected in Due 2.6.7 and Vue-Router 3.0.2. I am also using Vuetify and Vue-Head but don't think think this has anything to do with my problem.
index.js.
Does anyone have an idea what I could have been doing wrong. I actually suspect a bug in vue-router
when using multiple nested slots and keep-alive but cannot reproduce.
index.js
import Vue from "vue";
import VueRouter from "vue-router";
import App from "./App.vue";
import Start from "./Start.vue";
import SlotExample from "./SlotExample.vue";
const routes = [
{
path: "/start",
component: Start
},
{
path: "/slotExample/:id",
component: SlotExample,
props: true
}
];
const router = new VueRouter({ routes });
Vue.use(VueRouter);
new Vue({
render: h => h(App),
router,
components: { App }
}).$mount("#app");
App.vue
<template>
<div id="app">
<div>
<keep-alive><router-view/></keep-alive>
</div>
</div>
</template>
SlotExample.vue
<template>
<div>
<h1>Slot Example</h1>
<router-link to="/start"><a>start</a></router-link>
<router-link to="/slotExample/123">
<a>slotExample 123</a>
</router-link>
<slot-parent :id="id">
<slot-child
slot-scope="user"
:firstName="user.firstName"
:lastName="user.lastName"/>
</slot-parent>
</div>
</template>
<script>
import SlotParent from "./SlotParent.vue";
import SlotChild from "./SlotChild.vue";
export default {
name: "slotExample",
components: { SlotParent, SlotChild },
props: {
id: {
type: String,
required: true
}
}
};
</script>
SlotParent.vue
<template>
<div>
<div slot="header"><h1>SlotParent</h1></div>
<div slot="content-area">
<slot :firstName="firstName" :lastName="lastName" />
</div>
</div>
</template>
<script>
export default {
name: "slotParent",
props: {
id: {
type: String,
required: true
}
},
computed: {
firstName() {
if (this.id === "123") {
return "John";
} else {
return "Jane";
}
},
lastName() {
return "Doe";
}
}
};
</script>
SlotChild.vue
<template>
<div>
<h2>SlotChild</h2>
<p>{{ firstName }} {{ lastName }}</p>
</div>
</template>
<script>
export default {
name: "slotChild",
props: {
firstName: {
type: String,
required: true
},
lastName: {
type: String,
required: true
}
},
created() {
console.log("slotChild created");
},
mounted() {
console.log("slotChild mounted");
},
activated() {
console.log("slotChild activated");
}
};
</script>
I think you need to put SlotChild within keep-alive block.
Take a look at vue js doc about activated hook