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
I'm new to Vue.js and I'm still learning it. I bumped into this error which I don't know how to solve.
Here is my simple script:
<template>
<div v-for="item in array" :key="item.id">
{{item}}
</div>
</template>
<script>
export default {
data () {
return {
array: ['Lion','Bear','Fish','Bird']
}
}
}
</script>
And here is the error that come up:
Cannot use v-for on stateful component root element because it renders multiple elements.
1 |
2 | <div v-for="item in array" :key="item.id">
| ^^^^^^^^^^^^^^^^^^^^^
3 | {{item}}
4 | </div>
Is there anyone who knows how to fix this error?
Try also renaming variable from array to animalNames similar. And remove id from loop as there is not id element exist, instead you can use index
<template>
<div>
<div v-for="item,index in array" :key="index">
{{item}}
</div>
</div>
</template>
You must have a root tag. Try wrapping your looped div in another div.
<template>
<div>
<div v-for="item in array" :key="item.id">
{{item}}
</div>
</div>
</template>
<script>
export default {
data () {
return {
array: ['Lion','Bear','Fish','Bird']
}
}
}
</script>
Not too sure what is wrong here, it seems fine to me! I'm simply trying to update the data property display to true when I click the input within my component.
I have passed the data to the slot scope, so can't see that being the issue. It just simply won't update, using a function to toggle it works, however not what I really want to do, seems pointless.
<time-select>
<div slot-scope="{ time }" class="is-inline-block">
<label for="businessHoursTimeFrom"><i class="fas fa-clock"></i> From</label>
<input type="text" name="businessHoursTimeFrom[]" v-model="time" v-on:click="display = true">
</div>
</time-select>
The code behind:
<template>
<div>
<p>{{ display }}</p>
<slot :time="time" :display="display"></slot>
<div class="picker" v-if="display">
<p>Test</p>
</div>
</div>
</template>
<script>
export default {
props: [],
data: function () {
return {
time: '',
display: false
}
},
mounted() {
},
methods: {
}
}
</script>
I created two separated Vue components and I able to emit a message thru a bus.
How can I render/display the message in the component that receives the message.
Example of the Vue component that receives the message:
<template>
<div v-model="cars">
Car model: {{ model }}
<input type="button" #click="display" value="example" />
</div>
</template>
<script>
export default {
data() {
return {
cars: null
}
},
mounted() {
bus.$on('CARS_LOADED', (cars) => {
this.cars = cars;
});
},
methods: {
display()
{
console.log(this.cars);
}
}
}
</script>
I can successfully emit and received the message, however the car model is not updated. I checked the message received and it contains the "model" key with a right value.
I cannot see any error in the Vue console and however if I replace "{{ model }}" by "{{ cars }}" I can see the full message object updated.
I am using Vue 2.x.
Update:
I enclose an example:
https://jsfiddle.net/kvzvxk4f/1/
As you can see in the example I cannot render an specific field from the object, however I can render the object as string.
I think that you are misunderstanding some parts of the vue syntax.
How to access properties of an object:
You just need to write {{ car.model }} to access a property of an object.
How to iterate through an array in a template:
If you want to display all the cars in your template, you should write:
<div v-for="car in cars">
{{ car }}
</div>
As you see, the v-for directive allows you to iterate through an array.
What is v-model?
v-model is used to bind a variable to an input or a component.
<template>
<div>
<input type="text" v-model="foo" />
</div>
</template>
<script>
export default {
data () {
return {
foo: 'bar'
}
}
}
</script>
In that case, the foo property will be bound to the input text.
Last point:
In your case, to make it work, you also need to create a root element for your template, because a template can't have multiple root elements:
<template>
<div>
<div v-for="car in cars">
{{ car }}
</div>
</div>
</div>
I found the answer.
I just have to type property separated by ".". Like for example {{cars.model}}.
<template id="compo2">
<div>
<div>
{{ field.name }}
</div>
<div>
Received: {{ field }}
</div>
</div>
</template>
Example:
https://jsfiddle.net/zuhb7s8q/3/
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).