Is there a way to only display a slot if it has any content?
For example, I'm building a simple Card.vue component, and I only want the footer displayed if the footer slot has content:
Template
<template>
<div class="panel" :class="panelType">
<div class="panel-heading">
<h3 class="panel-title">
<slot name="title">
Default Title
</slot>
</h3>
</div>
<div class="panel-body">
<slot name="body"></slot>
<p class="category">
<slot name="category"></slot>
</p>
</div>
<div class="panel-footer" v-if="hasFooterSlot">
<slot name="footer"></slot>
</div>
</div>
</template>
Script
<script>
export default {
props: {
active: true,
type: {
type: String,
default: 'default',
},
},
computed: {
panelType() {
return `panel-${this.type}`;
},
hasFooterSlot() {
return this.$slots['footer']
}
}
}
</script>
In in View:
<card type="success"></card>
Since the above component doesn't contain a footer, it should not be rendered, but it is.
I've tried using this.$slots['footer'], but this returns undefined.
Does anyone have any tips?
It should be available at
this.$slots.footer
So, this should work.
hasFooterSlot() {
return !!this.$slots.footer;
}
Example.
You should check vm.$slots and also vm.$scopedSlots for it.
hasSlot (name = 'default') {
return !!this.$slots[ name ] || !!this.$scopedSlots[ name ];
}
CSS simplifies this a lot. Just use the following code and voila!
.panel-footer:empty {
display: none;
}
This is the solution for Vue 3 composition API:
<template>
<div class="md:grid md:grid-cols-5 md:gap-6">
<!-- Here, you hide the wrapper if there is no used slot or empty -->
<div class="md:col-span-2" v-if="hasTitle">
<slot name="title"></slot>
</div>
<div class="mt-5 md:mt-0"
:class="{'md:col-span-3': hasTitle, 'md:col-span-5': !hasTitle}">
<div class="bg-white rounded-md shadow">
<div class="py-7">
<slot></slot>
</div>
</div>
</div>
</div>
</template>
<script>
import {ref} from "vue";
export default {
setup(props, {slots}) {
const hasTitle = ref(false)
// Check if the slot exists by name and has content.
// It returns an empty array if it's empty.
if (slots.title && slots.title().length) {
hasTitle.value = true
}
return {
hasTitle
}
}
}
</script>
Now, in Vue3 composition API , you can use useSlots.
<script setup>
import { useSlots } from 'vue'
const slots = useSlots()
</script>
<template>
<div v-if="slots.content" class="classname">
<slot name="content"></slot>
</div>
</template>
In short do this in inline:
<template lang="pug">
div
h2(v-if="$slots.title")
slot(name="title")
h3(v-if="$slots['sub-title']")
slot(name="sub-title")
</template>
I have ran into a similiar issue but across a wide code base and when creating atomic design structured components it can be tiring writing hasSlot() methods all the time and when it comes to TDD - its one more method to test... Saying that, you can always put the raw logic in a v-if but i have found that the template end up cluttered and harder to read on occasions especially for a new dev checking out the code structure.
I was tasked to find out a way of removing parent divs of slots when the slot isnt provided.
Issue:
<template>
<div>
<div class="hello">
<slot name="foo" />
</div>
<div class="world">
<slot name="bar" />
</div>
</div>
</template>
//instantiation
<my-component>
<span slot="foo">show me</span>
</my-component>
//renders
<div>
<div class="hello">
<span slot="foo">show me</span>
</div>
<div class="world"></div>
</div>
as you can see, the issue is that i have an almost 'trailing' div, that could provide styling issues when the component author decides there is no need for a bar slot.
ofcourse we could go <div v-if="$slots.bar">...</div> or <div v-if="hasBar()">...</div> etc but like i said - that can get tiresome and eventually end up harder to read.
Solution
My solution was to make a generic slot component that just rendered out a slot with a surrounding div...see below.
//slot component
<template>
<div v-if="!!$slots.default">
<slot />
</div>
</template>
//usage within <my-component/>
<template>
<div>
<slot-component class="hello">
<slot name="foo"/>
</slot-component>
<slot-component class="world">
<slot name="bar"/>
</slot-component>
</div>
</template>
//instantiation
<my-component>
<span slot="foo">show me</span>
</my-component>
//renders
<div>
<div class="hello">
<span>show me</span>
</div>
</div>
I came into use-case issues when trying this idea and sometimes it was my markup structure that needed to change for the benefit of this approach.
This approach reduces the need for small slot checks within each component template. i suppose you could see the component as a <conditional-div /> component...
It is also worth noting that applying attributes to the slot-component instantiation (<slot-component class="myClass" data-random="randomshjhsa" />) is fine as the attributes trickle into the containing div of the slot-component template.
Hope this helps.
UPDATE
I wrote a plugin for this so the need for importing the custom-slot component in each consumer component is not needed anymore and you will only have to write Vue.use(SlotPlugin) in your main.js instantiation. (see below)
const SLOT_COMPONENT = {
name: 'custom-slot',
template: `
<div v-if="$slots.default">
<slot />
</div>
`
}
const SLOT_PLUGIN = {
install (Vue) {
Vue.component(SLOT_COMPONENT.name, SLOT_COMPONENT)
}
}
export default SLOT_PLUGIN
//main.js
import SlotPlugin from 'path/to/plugin'
Vue.use(SlotPlugin)
//...rest of code
Initially I thought https://stackoverflow.com/a/50096300/752916 was working, but I had to expand on it a bit since $scopeSlots returns a function which is always truthy regardless of its return value. This is my solution, though I've come to the conclusion that the real answer to this question is "doing this is an antipattern and you should avoid it if possible". E.g. just make a separate footer component that could be slotted in.
Hacky solution
hasFooterSlot() {
const ss = this.$scopedSlots;
const footerNodes = ss && ss.footer && ss.footer();
return footerNodes && footerNodes.length;
}
Best Practice (helper component for footer)
const panelComponent = {
template: `
<div class="nice-panel">
<div class="nice-panel-content">
<!-- Slot for main content -->
<slot />
</div>
<!-- Slot for optional footer -->
<slot name="footer"></slot>
</div>
`
}
const footerComponent = {
template: `
<div class="nice-panel-footer">
<slot />
</div>
`
}
var app = new Vue({
el: '#app',
components: {
panelComponent,
footerComponent
},
data() {
return {
name: 'Vue'
}
}
})
.nice-panel {
max-width: 200px;
border: 1px solid lightgray;
}
.nice-panel-content {
padding: 30px;
}
.nice-panel-footer {
background-color: lightgray;
padding: 5px 30px;
text-align: center;
}
<script src="https://unpkg.com/vue#2.6.11/dist/vue.min.js"></script>
<div id="app">
<h1>Panel with footer</h1>
<panel-component>
lorem ipsum
<template #footer>
<footer-component> Some Footer Content</footer-component>
</template>
</panel-component>
<h1>Panel without footer</h1>
<panel-component>
lorem ipsum
</panel-component>
</div>
Hope I understand this right. Why not using a <template> tag, which is not rendered, if the slot is empty.
<slot name="foo"></slot>
Use it like this:
<template slot="foo">
...
</template>
For Vue 3:
Create an utility function
//utils.js
function isSlotHasContent(slotName, slots) {
return Boolean(!!slots[slotName] && slots[slotName]()[0].children.length > 0);
}
In your component:
<script setup>
import { isSlotHasContent } from 'path/to/utils.js';
const slots = useSlots();
// "computed" props has a better performance
const isFooSlotHasContent = computed(() => isSlotHasContent('foo', slots));
</script>
<template>
<div>
<div v-if="isFooSlotHasContent">
<slot name="foo" />
</div>
<div v-if="!isFooSlotHasContent">
Some placeholder
</div>
</div>
</template>
TESTED
So this work for me in vue 3:
I use onMounted to first get the value, and then onUpdate so the value can update.
<template>
<div v-if="content" class="w-1/2">
<slot name="content"></slot>
</div>
</template>
<script>
import { ref, onMounted, defineComponent, onUpdated } from "vue";
export default defineComponent({
setup(props, { slots }) {
const content = ref()
onMounted(() => {
if (slots.content && slots.content().length) {
content.value = true
}
})
onUpdated(() => {
content.value = slots.content().length
console.log('CHECK VALUE', content.value)
})
})
</script>
#Bert answer does not seem to work for dynamic templates like <template v-slot:foo="{data}"> ... </template>.
i ended up using:
return (
Boolean(this.$slots.foo) ||
Boolean(typeof this.$scopedSlots.foo == 'function')
);
I like the Solution of #AlexMA however in my case I needed to pass props to the function in order to get the nodes to show up.
Here is an example of how I am passing the "row" to the scoped slot, in my case the row contains a type param that I want to test against in the calling component.
<other-component>
<template v-slot:expand="{ row }" v-if="!survey.editable">
<div v-if="row.type != 1" class="flex">
{{ row }}
</div>
</template>
</other-component>
In "other-component" I have the template defined as
<template>
<div>
<div v-for="(row, index) in rows">
{{ hasSlotContent(row) }}
<slot name="expand" :row="row"> </slot>
</div>
</div>
</template>
Because the v-slot requires "row" to be passed to it I created a a method
methods:{
hasSlotContent(row){
const ss = this.$scopedSlots
const nodes = ss && ss.expand && ss.expand({ row: row })
return !!(nodes && nodes.length)
}
}
I call this on each iteration so that it can evaluate itself and give back the appropriate response.
you can use the "hasSlotContent(row)" method where-ever you need it, in my example I'm just outputting the truthy value to the DOM.
I hope this helps someone come to a quicker solution.
Reposting a Vue 3 solution from Github, which also works with Options API, since there was a fairly upvoted method from an Issue there:
The comment itself: https://github.com/vuejs/core/issues/4733#issuecomment-1024816095
The function (remove types if you're not writing TypeScript):
import {
Comment,
Text,
Slot,
VNode,
} from 'vue';
export function hasSlotContent(slot: Slot|undefined, slotProps = {}): boolean {
if (!slot) return false;
return slot(slotProps).some((vnode: VNode) => {
if (vnode.type === Comment) return false;
if (Array.isArray(vnode.children) && !vnode.children.length) return false;
return (
vnode.type !== Text
|| (typeof vnode.children === 'string' && vnode.children.trim() !== '')
);
});
}
This works just as fine, if you delete the slotProps argument (unless you need it).
Related
I'm trying to render a header only if there's a text or a populated slot inside of it.
I tried:
<div
class="flex py-sm px-md w-full align-middle rounded-t-xl"
v-if="props.title || $slots.header"
:class="[`bg-${props.headerColor}`]"
>
<p class="text-bo-xl font-bold" :class="`text-${props.titleTextColor}`">
{{ props.title }}
</p>
<slot name="header"></slot>
</div>
But the div renders anyway, even if the slot is empty. I think it considers the slot present even if it's not populated.
Any ideas?
sorry for the late response. If I utilize computed() it seems to work:
<template>
<section>
<h4>lorem</h4>
<div v-if="hasHeaderSlot">
<h2>ipsum</h2>
<slot name="header"></slot>
</div>
</section>
</template>
<script>
import { computed } from 'vue';
export default {
setup(_, { slots }) {
const hasHeaderSlot = computed(() => slots.header && slots.header());
return {
hasHeaderSlot,
};
},
};
</script>
I hope this helps. With best regards
One thing that I have been struggling to figure out how to do better is modals. Currently, I am registering the modal component on each Vue that needs it. However, this feels rather sloppy, as I am having to register the component several times. Even using mix-ins just does not feel like an elegant solution. What would be optimal to be able to do is to mimic JavaScript's alert() method on the Vue instance. For example, be able to call this.ShowModal(Header, Body)
However, from my understanding, there is no way to accomplish this
Take for example my Modal example. You could have a modal template like this:
<script type="text/x-template" id="modal-template">
<transition name="modal">
<div class="modal-mask">
<div class="modal-wrapper">
<div class="modal-container">
<div class="modal-header">
<slot name="header">
default header
</slot>
</div>
<div class="modal-body">
<slot>
</slot>
</div>
<div class="modal-footer">
<slot name="footer">
default footer
<button class="modal-default-button" #click="$emit('close')">
OK
</button>
</slot>
</div>
</div>
</div>
</div>
</transition>
</script>
Then you would have to reference the component over and over again like this
<template>
<button #click="displayModal">Display the Modal Alert</button>
<modal v-if="showModal" #close="showModal = false">
<h3 slot="header"> This is a good header </h3>
<p>
Look at me I am the body! You have seen me {{displayCount}} times!
</p>
</modal>
</template>
<script>
components: {modal},
data: {
showModal: false,
displayCount: 0
},
methods: {
displayModal(){
this.displayCount++
this.showModal = true;
}
}
</script>
If you wanted to reuse the component for several messages from within the parent you would then have to add several more variables to store things such as the header and body. You could put some of the logic into a mixin but you would still have to have the clutter of adding the modal component and possibly the mixin.
This brings us to the question. Is there a way to create a function in the Vue instance that would allow for us to dynamically create a Modal component and fill in the slots with arguments passed to the function? e.g. this.ShowModal("This is a good header", "Look at me I am the body!")
Use Vue.extend() create a "modal" constructor and create a instance,you can mount it to DOM dynamically by $mount or other ways
In Modal example:
modal.vue:
<template>
<div>
{{message}} //your modal content
</div>
</template>
<script>
export default {
name: 'modal',
data(){
return {
message: '',
}
},
methods:{
/************/
close () {
/****this.$destroy()****/
}
}
}
</script>
modal.js:
import myModal from 'modal.vue'
import Vue from 'vue'
const modalConstructor = Vue.extend(myModal)
const modal = (options,DOM)=>{
const modalInstance = new modalConstructor({data:options})
modalInstance.vm = modalInstance.$mount() //get vm
const dom = DOM || document.body // default DOM is body
dom.appendChild(modalInstance.vm.$el) // mount to DOM
return modalInstance.vm
}
export default modal
now you can create a Modal component by a function like this:
import showModal from 'modal.js'
showModal({message:"..."})
Im super new to Vue.
i have a Vue-CLI app, which have a navbar and content.
Navbar is common to all pages, but i want to customize in each page whit some additional content.
Example:
Common-> home | about
View home -> home | about | your are in view home
View about -> home | about | your are in view about
router/index.js
import Vue from 'vue';
import VueRouter from 'vue-router';
import Home from '../views/Home.vue';
import NavBar from '#/components/NavBar.vue';
Vue.use(VueRouter);
Vue.component('nav-bar', NavBar);
//...
components/navbar.vue
<template>
<div>
<b-nav-item to="/">home</b-nav-item>
<b-nav-item to="/about">about</b-nav-item>
{{customContent}}
</div>
</template>
<script>
export default {
name: 'NavBar',
props: {
customContent: {
type: String,
default: 'default Content',
},
},
};
</script>
App.vue
<template>
<div id="app">
<nav-bar />
<div class="container-fluid">
<router-view />
</div>
</div>
</template>
views/home.vue
<template>
<div class="row">
<div class="col-12">
<image-card :images="images"/>
</div>
</div>
</template>
<script>
//how can i customize here the navbar by adding for example 'your are in view home'???
</script>
Thanks so much!
There are a few ways in which you can solve this problem. I'll list two of them.
1. Update NavBar by $route
In this approach, the NavBar component already contains all of the possible combinations, and will display the relevant portion(s) depending on what $route contains.
Here's some pseudo code:
navbar.vue
<template>
<div class="navbar">
<div class="navbar-left>
APPNAME
</div>
<div v-if="name === 'landing'">
...
</div>
<div v-else-if="name === 'room'">
...
</div>
</div>
</template>
App.vue
<template>
<div id="app">
<NavBar :name="$route.name"/>
<main>
<router-view/>
</main>
</div>
</template>
In this example, the NavBar component is very rigid, and doesn't really lend itself to much reuse. However, it does encapsulate all the relevant code relating to the nav bar.
2. Extensible NavBar with slots
In this approach, the NavBar only provides the bare-minimum to create a nav bar. The rest of the route-specific elements are to be filled in by the views.
navbar.vue
<template>
<div class="navbar">
<div class="navbar-left">
<div class="navbar-brand">
APPNAME
</div>
<slot name="left"></slot>
</div>
<div class="navbar-right">
<slot name="right"></slot>
</div>
</div>
</template>
App.vue
<template>
<div id="app">
<router-view/>
</div>
</template>
landing.vue
<template>
<div>
<header>
<NavBar>
<template slot="right">
<span>
<div class="navbar-item">
<div class="buttons">
<button class="button" #click="...">Start Watching</button>
</div>
</div>
</span>
</template>
</NavBar>
</header>
<main>
...
</main>
</div>
</template>
This approach has a bit of repetition in terms of DOM elements, but gives you an extremely flexible NavBar that can be customized by each view.
The approach you want to use depends on what is important to you.
If strict encapsulation is what you want, then you may want to use approach 1, as all of the NavBar-related code is contained within a single file.
However, if you believe that there is a potential for reuse, or if you would like all view-related code to live in one place, then it makes sense to use slots instead and extend the NavBar as required by each view.
I use a breadcrumb to achieve a similar thing. Just an idea but Vue router allows you to add meta data to the current route which you always have access to
router.js
path: '/add',
name: 'add',
component: () => import(/* webpackChunkName: "add" */ '../../views/Add.vue'),
meta: {
breadCrumb: [
{ name: 'Add New' }
]
},
Notice the meta object attached to the route.. this will be used to describe the current view.
Breadcrumb.vue component
<template>
<div class="breadcrumb">
<ul class="d-flex m-0 p-0"
<li
v-for="(breadcrumb, idx) in breadcrumbList"
:key="idx">
{{ breadcrumb.name }}
</li>
</ul>
</div>
</template>
<script>
export default {
name: 'Breadcrumb',
data () {
return {
breadcrumbList: []
}
},
mounted () { this.updateList() },
watch: { '$route' () { this.updateList() } },
methods: {
routeTo (pRouteTo) {
if (this.breadcrumbList[pRouteTo].link) this.$router.push(this.breadcrumbList[pRouteTo].link)
},
updateList () { this.breadcrumbList = this.$route.meta.breadCrumb },
formatPath(path) {
const newPath = path.replace(/\//g, " > ")
return newPath
}
}
}
</script>
And then you can import the breadcrumb into your navbar or where ever you would like to place it
<Breadcrumb class="breadcrumb" />
import Breadcrumb from '#/components/Breadcrumb.vue'
components: {Breadcrumb}
So basically the breadcrumb will always watch your current route and change the data based on the meta data you provide in your router.js file
You can access to router name like this:
<div v-if="this.$route.name == 'home'">
<HeaderTransparent />
</div>
<div v-else>
<HeaderWhite />
</div>
Update: Here's a simplified version of what I'm trying to achieve here (from the threaded conversation below):
Accept Component A - Accept Component B - Accept a condition - if
condition is true : wrap Component B with Component A [and render]- else only
render component B.
I'm interested in creating a component that renders a wrapper conditionally. I figured a theoretical approach like this would probably be best**:**
<template>
<div>
<slot v-if="wrapIf" name="wrapper">
<slot name="content"></slot>
</slot>
<slot v-else name="content"></slot>
</div>
</template>
<script>
export default {
props: {
wrapIf: Boolean,
}
}
</script>
Then when we implement, it would look something like this:
...
<wrapper-if :wrap-if="!!link">
<a :href="link" slot="wrapper"><slot></slot></a>
<template slot="content">
content
</template>
</wrapper-if>
The idea being that, in this case, if there is a link, then let's wrap the content with the wrapper slot (which can be any component/element). If there isn't, then let's just render the content without the wrapped link. Pretty simple logic, but it seems that I'm misunderstanding some basic vue functionality because this particular example does not work.
What is wrong with my code or is there some kind of native api that already achieves this or perhaps a dependency that does this sort of thing already?
The output should look like this:
wrapIf === true
<a href="some.link">
content
</a>
wrapIf === false
content
Just focus on the content itself, and let the component worry about whether or not to wrap the default or named content slot.
If you need the wrapper to be dynamic, a dynamic component should solve that. I've updated my solution accordingly. So if you need the wrapper to be a label element, just set the tag property to it, and so on and so forth.
const WrapperIf = Vue.extend({
template: `
<div>
<component :is="tag" v-if="wrapIf" class="wrapper">
<slot name="content"></slot>
</component>
<slot v-else name="content"></slot>
</div>
`,
props: ['wrapIf', 'tag']
});
new Vue({
el: '#app',
data() {
return {
link: 'https://stackoverflow.com/company',
tagList: ['p', 'label'],
tag: 'p',
wrap: true
}
},
components: {
WrapperIf
}
})
.wrapper {
display: block;
padding: 10px;
}
p.wrapper {
background-color: lightgray;
}
label.wrapper {
background-color: lavender;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
<div id="app">
<wrapper-if :wrap-if="wrap" :tag="tag">
<a :href="link" slot="content">
content
</a>
</wrapper-if>
<div>
Change wrapper type:
<select v-model="tag">
<option v-for="tag in tagList">{{tag}}</option>
</select>
</div>
<button #click="wrap = !wrap">Toggle wrapper</button>
</div>
I am new to Vuejs. This is what I need to do.
<div v-for="r in records">
<div v-if="r.something">
<div id="x">
{{ r. something}}
more of r here.
</div>
</div>
<div v-else id="x">
same div as in the block above.
</div>
</div>
What I want do is not define div with id x two times as it is huge.
Make your 'div' a component and refer to it in both places.
There are many ways to define your component. This is example shows just one. If you are using WebPack, use a single file component. You can then have your script, html, and css all in one file that gets precompiled. That's the best way to manage your 'huge' div. Then you can continue to refactor and break it up into more components.
const myComponent = {
template: "<div :id='id'>HELLO, my id is {{id}}. r.foo is {{r.foo}} </div>",
props: {
id: String
},
data() {
return {
r: {
foo: 'bar'
}
}
}
}
<div v-for="r in records">
<div v-if="r.something">
<my-component id='x' />
</div>
<div v-else id="x">
<my-component id='x' />
</div>
</div>