conditional class binding in list using props in vue js - vue.js

progressbar component receives props from parent component name activeStep that its value is active index of progressbar. my challenge is while rendering list of progressbar i want to set active class to li s that less than value of active step property or equal to value
how can i do that?
<template>
<div>
<ul class="progressbar">
<li v-for="(progressbarCase,index) in progressbarCases" :key="progressbarCase.id">
{{progressbarCase.title}}
</li>
</ul>
</div>
</template>
<style lang="css">
#import "../assets/stylesheet/progressbar.css";
</style>
<script>
export default {
props: ['activeStep'],
data () {
return {
progressbarCases: [
{title: 'first'},
{title: 'second'},
{title: 'third'}
]
}
}
}
</script>

If you want add class conditional, you can use :class="". For example: :class="true ? 'active' : 'disable'". with this,if condition is true: class="active" else class="disable"

Quite simple, if you have more than one conditionnal class, you need to define the :class attribute as an object like this:
<li :class="{
'a-conditional-class': true,
'an-other-conditional-class-but-not-displayed': false,
}">
</li>
For your information, you can also couple conditional and unconditional classes !
And in one :class attribute, like this:
<li :class="[
'an-unconditional-class',
{
'a-conditional-class': true,
'an-other-conditional-class-but-not-displayed': false,
}
]">
</li>
Have a look on the official documentation for more information about Class an style binding: https://v2.vuejs.org/v2/guide/class-and-style.html#ad

Related

How can I modify template variables declared with :set?

I have the following code (vue v3.2.33)
<template v-for="route of routes" :key="route.name">
<li :set="open = false">
<div class="collapse"
#click="open = !open"
:class="[open ? 'collapse-is-open' : '']">
</div>
</li>
</template>
Basically each li has a collapse and opens with the class collapse-is-open.
I tried to use a variable with the :set attribute and modify that variable but it doesn't seem to work.
If that can't be working, what would be the other way of doing this ? An object based on the value I set in :key that keeps track of all the states?
:set is syntax for the v-bind directive. It binds a property/attribute on the element, but there is no such set property for <li>. I think you're trying to create an ad-hoc variable named open for each <li>, but that feature doesn't exist in Vue (perhaps you're thinking of petite-vue's v-scope).
One solution is to create a separate data structure that contains the open-state of each <li>, and use that to update the class binding:
export default {
data() {
return {
routes: [⋯],
open: {} // stores open-state of each route item
}
}
}
<template v-for="route of routes" :key="route.name">
<li>
<div class="collapse"
#click="open[route.name] = !open[route.name]"
:class="[open[route.name] ? 'collapse-is-open' : '']">
</div>
</li>
</template>
demo 1
Alternatively, you could add that property to each array item in routes:
export default {
data() {
return {
routes: [
{
name: 'Route 1',
open: false,
},
{
name: 'Route 2',
open: false,
},
{
name: 'Route 3',
open: false,
},
],
}
},
}
<template v-for="route of routes" :key="route.name">
<li>
<div class="collapse"
#click="route.open = !route.open"
:class="[route.open ? 'collapse-is-open' : '']">
</div>
</li>
</template>
demo 2

How to search within nested objects

I have done my research trying to figure out how to achieve what I am describing below, however I had no luck.
In my Algolia index, some records have nested objects.
For example, title and subtitle attributes are of the following format:
title:
{
"en": "English title",
"gr": "Greek title"
}
I would like to execute queries only for a specific subset (in our example "en" or "gr") of these attributes, withoute "exposing" any facet in the UI — language selection would ideally be done “automatically” based on a variable (lang) passed to the Vue component with props. I am using Laravel Scout package with default Vue implementation, as described in documentation here.
My InstantSearch implementation is pretty simple, I am not defining anything specific regarding queries and searchable attributes, I am currently using all the default functionality of Algolia.
<template>
<ais-instant-search
:search-client="searchClient"
index-name="posts_index"
>
<div class="search-box">
<ais-search-box placeholder="Search posts..."></ais-search-box>
</div>
<ais-hits>
<template
slot="item"
slot-scope="{ item }"
>
<div class="list-image">
<img :src="'/images/' + item.image" />
</div>
<div class="list-text">
<h2">
{{ item.title }}
</h2>
<h3>
{{ item.subtitle }}
</h3>
</div>
</template>
</ais-hits>
</ais-instant-search>
</template>
<script>
import algoliasearch from 'algoliasearch/lite';
export default {
data() {
return {
searchClient: algoliasearch(
process.env.ALGOLIA_APP_ID,
process.env.ALGOLIA_SEARCH
),
route: route,
};
},
props: ['lang'],
computed: {
computedItem() {
// computed_item = this.item;
}
}
};
</script>
I would like to somehow pass an option to query “title.en” and “subtitle.en” when variable lang is set to “en”. All this, without the user having to select “title.en” or “subtitle.en” in the UI.
Update
Maybe computed properties is the path to go, however I cannot find how to reference search results/hits attributes (eg item.title) within computed property. It is the code I have commented out.
I think, you can use computed property. Just transform current item according to the current language variable.
new Vue({
template: "<div>{{ computedItem.title }}</div>",
data: {
langFromCookie: "en",
item: {
title: {
en: "Hello",
ru: "Привет"
}
}
},
computed: {
computedItem() {
const item = JSON.parse(JSON.stringify(this.item));
for (value in item) {
if (typeof item[value] === "object" && Object.keys(item[value]).includes(this.langFromCookie))
item[value] = item[value][this.langFromCookie];
}
return item;
}
}
}).$mount("#app")
<div id="app"></div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
If lang variable is available via props, you can check that inside list-text class and return {{title.en}} or {{title.gr}} accordingly by passing a dynamic lang value title[lang] like below
...
<div class="list-text">
<h2>
{{ item.title[lang] }}
</h2>
<h3>
{{ item.subtitle[lang] }}
</h3>
</div>
If you want to make a request according to lang prop when component mounts ,then you can make a request inside mounted() method then query like below
mounted() {
axios.get(`/getSomethingWithLang/:${this.item.title[this.lang]}`)
...
}

Using Slots or slot-scopes in v-for loops to access properties?

I'm having a difficult time understanding slots for some reason and why they should even be used. The only reason I can think of that would be nice for usuage is if we can reference specific properties within a v-for loop of an element and output different templates quicker perhaps...
So, am thinking, and possibly I could be wrong in thinking this, but if I have a variable like so:
<script>
const items: [
{
label: 'My Label',
url: '#',
headerTitle: 'My Header Title'
},
{
label: 'My Label 2',
url: 'https://www.myurl.com',
headerTitle: 'My Header Title 2'
},
{
label: 'My Label 3',
url: 'https://www.myurl3.com'
}
]
export default {
data () {
return {
items: items
}
}
}
</script>
And than in the template, possibly this:
<template>
<div v-for="(item, index) in items" :key="item.id">
<template slot-scope="headerTitle">
<h1>{{ item.headerTitle }}</h1>
</template>
<template slot-scope="label">
<div class="mylabel">
{{ item.label }}
</div>
</template>
<template slot-scope="url">
<a :href="item.url">{{ item.label }}</a>
</template>
</div>
</template>
I don't know if this makes sense or not, but basically using the property as a slot-scope and than for everytime that property is defined, it will output something. But this doesn't work properly. Is this not what slot-scopes are for within component v-for loops? Is this not how to use these properties of an array of objects?
This kinda makes sense to me. Anyways to do it like this perhaps?

Conditional link behavior in VueJS

Couldn't find a proper name for the title, will be glad if someone figures out a better name.
I have a component which represents a product card. The whole component is wrapped in <router-link> which leads to product page.
However I have another case, when I do not need the component to lead to a product page, but instead I need to do some other action.
The only solution I found is to pass a callback function as a prop, and based on this, do something like:
<router-link v-if="!onClickCallback">
... here goes the whole component template ...
</router-link>
<div v-if="onClickCallback" #click="onClickCallback">
... here again goes the whole component template ...
</div>
How can I do this without copy-pasting the whole component? I tried to do this (real code sample):
<router-link class="clothing-item-card-preview"
:class="classes"
:style="previewStyle"
:to="{ name: 'clothingItem', params: { id: this.clothingItem.id }}"
v-on="{ click: onClick ? onClick : null }">
However I got this: Invalid handler for event "click": got null
Plus not sure if it's possible to pass prevent modificator for click and this just looks weird, there should be a better architectural solution
Commenting on the error, you could use an empty function instead of null, in the real code snippet
<router-link class="clothing-item-card-preview"
:class="classes"
:style="previewStyle"
:to="{ name: 'clothingItem', params: { id: this.clothingItem.id }}"
v-on="{ click: onClick ? onClick : null }">
This should works (replace a for "router-link" then insert right properties)
Further infos :
https://fr.vuejs.org/v2/guide/components-dynamic-async.html
v-bind is simply an Object where each keys is a props for your component, so here, I programmatically defined an object of properties depending on the wrapper (router link or a simple div). However we cannot do this for events (of course we could create our own event listener but it's a little bit tricky) so I simply but an handle method.
new Vue({
el: "#app",
data: {
products : [{onClickCallback : () => { alert("callback"); return true;}}, {}, {}]
},
methods : {
handleClick(product, event) {
if (!product.onClickCallback) return false
product.onClickCallback()
return true
},
getMyComponentName(product) {
if (product.onClickCallback) return "div"
return "a"
},
getMyComponentProperties(product) {
if (product.onClickCallback) return {is : "div"}
return {
is : "a",
href: "!#"
}
}
}
})
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
<div id="app">
<component
v-for="(product, index) in products"
:key="index"
v-bind="getMyComponentProperties(product)"
#click="handleClick(product, $event)"
>
<div class="product-card">
<div class="product-card-content">
<span v-show="product.onClickCallback">I'm a callback</span>
<span v-show="!product.onClickCallback">I'm a router link</span>
</div>
</div>
</component>
</div>
Do you have to use a <router-link>? If it can safely be a <div>, you could use something like
<div #click="handleClick" ...>
<!-- component template -->
</div>
and
methods: {
handleClick (event) {
if (this.onClickCallback) {
this.onClickCallback(event)
} else {
this.$router.push({ name: 'clothingItem', ... })
}
}
}
See https://router.vuejs.org/guide/essentials/navigation.html

When using conditional rendering, how do I prevent repeating the child components on each condition?

Scenario
I have a custom button component in Vue:
<custom-button type="link">Save</custom-button>
This is its template:
// custom-button.vue
<template>
<a v-if="type === 'link'" :href="href">
<span class="btn-label"><slot></slot></span>
</a>
<button v-else :type="type">
<span class="btn-label"><slot></slot></span>
</button>
</template>
You can see from the template that it has a type prop. If the type is link, instead of the <button> element, I am using <a>.
Question
You'll notice from the template that I repeated the child component, i.e. <span class="btn-label"><slot></slot></span> on both root components. How do I make it so that I won't have to repeat the child components?
In JSX, it's pretty straightforward. I just have to assign the child component to a variable:
const label = <span class="btn-label">{text}</span>
return (type === 'link')
? <a href={href}>{label}</a>
: <button type={type}>{label}</button>
In this situation, I would probably opt to write the render function directly since the template is small (with or without JSX), but if you want to use a template then you can use the <component> component to dynamically choose what you want to render as that element, like this:
Vue.component('custom-button', {
template: '#custom-button',
props: [
'type',
'href',
],
computed: {
props() {
return this.type === 'link'
? { is: 'a', href: this.href }
: { is: 'button', type: this.type };
},
},
});
new Vue({
el: '#app',
});
<script src="https://rawgit.com/vuejs/vue/dev/dist/vue.js"></script>
<div id="app">
<custom-button type="button">Button</custom-button>
<custom-button type="submit">Submit</custom-button>
<custom-button type="link" href="http://www.google.com">Link</custom-button>
</div>
<template id="custom-button">
<component v-bind="props">
<span class="btn-label"><slot></slot></span>
</component>
</template>
Well you could always create a locally registered component...
// in custom-button.vue
components : {
'label' : {template : '<span class="btn-label"><slot></slot></span>'}
}