Vue refs undefined in modal - vue.js

I do have a for loop and inside i want to have a modal for each image
<div class="col pb-3" v-for="(item, index ) in img" :key="index" style="width: 300px;height:auto;">
<img v-b-modal="'modal-'+index" :ref="'image'" #mouseover="mouseOver" #mouseleave="mouseOut" /><br>
<b-modal :id="'modal-'+index" title="BootstrapVue">
<p class="my-4">Hello from modal - {{index}}</p>
<img :ref="'imagex'" />
</b-modal>
<div class="progress pt-2 mt-1" style="width: 100px;margin: 0 auto;">
<div class="progress-bar " :style="[{'width':width[index]+'px'}]" role="progressbar"
aria-valuenow="0" ref="'progress'" aria-valuemin="0" aria-valuemax="100"></div>
</div>
</div>
In methods i am giving src value to each image that has :ref="'image'" and i can actually give a src to them its work fine but, i also want be able to give src value images in modal. Its called :ref="'imagex'" but its undefined.
this.$refs.image[i].src = event.target.result //works
this.$refs.imagex[i].src = event.target.result //undefined
What is the problem an is there anyway to solve it ?

When used on elements/components with v-for, the registered reference will be an Array containing DOM nodes or component instances.
An important note about the ref registration timing: because the refs themselves are created as a result of the render function, you cannot access them on the initial render - they don’t exist yet! $refs is also non-reactive, therefore you should not attempt to use it in templates for data-binding.
.
can use it in events and only at mounted function.
https://v2.vuejs.org/v2/api/#ref

Related

Vue - passing v-for index from parent to child component

I've done the research but can't find a good answer. My parent and child component code is below. How do I pass the index for the v-for loop in the parent to the child component for use there? I want to hide any of the gauges past #4 for mobile screens, but show all of them on a desktop.
Parent:
<div class="col-md-8 col-xs-6">
<div class="row flex-nowrap">
<data-block
v-for="(gauge, index) in device.gauges"
:metric="gauge.metric"
:value="gauge.value"
:unit="gauge.unit"
:alarm="gauge.alarm"
:idx="index">
</data-block>
</div>
</div>
Child:
app.component('data-block', {
props: ['alarm', 'metric','value','unit','idx'],
template: `<div v-bind:class="'col card px-0 text-center border' + ((alarm) ? ' border-danger':' border-success') + ((idx > 3) ? ' d-none d-md-block':'')">\
<div class="card-header p-1">{{metric}}</div>\
<div class="card-body p-1 align-middle">\
<h1 class=" text-center display-1 font-weight-normal text-nowrap">{{value}}</h1>\
</div>\
<div class="card-footer p-1">{{unit}}</div>\
</div>`,
created: ()=> console.log(this.idx) //yields "undefined"
})
You're passing the idx prop correctly, but Instead of checking its value inside created hook, try displaying it in the template instead, to make sure it's not an issue with timing (it might not be defined when the child component is created):
<div>{{idx}}</div>
Also, to make the code easier to read and write, I would suggest you to move the static classes to class attribute and the dynamic classes to v-bind:class attribute, and also make it multiline:
template: `
<div
class="col card px-0 text-center border"
:class="{
'd-none d-md-block': idx > 3,
'border-danger': alarm,
'border-success': !alarm
}"
>
...
`

v-on:click not working - dynamically added html element

I am trying to get all images for a category using Vue
<div class="col-md-12 col-sm-2 p-2">
<a v-on:click="onCategoryManageImageClick($event)" data-target="#location-
category-images">
</span>
</a>
</div>
So the event onCategoryManageImageClick ($event) does not work, if I am adding a html block and then click on get image button.
this is index.js
methods:{
onImagesTabClick(){
this.$root.$emit('activated-tab:location-images');
},
onCategoriesTabClick(){
window.j1App.eventBus.$emit("j1-location-image-list:shown");
},
onCategoryManageImageClick: function(event) {console.log('working event..');
event.preventDefault();
window.j1App.eventBus.$emit("j1-location-category-image-
list:shown",event.currentTarget.id);
}
}
So basically it need to to work like we do in jQuery
$(document).on('click',function{
})
So it works either page load or if adding any new html element on DOM. same I want in Vue.
You cannot alter the Vue template outside of Vue. That won't work. Vue compiles the template once when starting up and adds the event listeners to the rendered elements. If you add elements afterwards, Vue will not know about them.
The correct way of doing this would be to add those new elements in Vue.
<div
class="col-md-12 col-sm-2 p-2"
v-for="item in items"
:key="item.id"
>
<a
v-on:click="onCategoryManageImageClick($event, item)"
data-target="#location-category-images"
>
</a>
</div>
See https://v2.vuejs.org/v2/guide/list.html for documentation. In this case you need the items array variable in data and add more array elements to it, if you need more links.
Try raplacing your a tag with p
<div class="col-md-12 col-sm-2 p-2">
<p v-on:click="onCategoryManageImageClick" data-target="#location-
category-images">
</p>
</div>

VueJS transition on computed values

I want to animate a block with posts that can be filtered.
Some filters trigger a computed method filteredPosts and they are assigned to a component liek that <block-article :posts="filteredPosts" />
In my <block-article> component I have something like that :
<template>
<div class="posts">
<div v-for="post in posts" :key="post.id"></div>
</div>
</template>
I want div .posts animate like a translation bottom/fade out on disappear and translation top/ fade in on appear.
I tried that :
<template>
<transition name="slide-fade">
<div class="posts">
<div v-for="post in posts" :key="post.id"></div>
</div>
</transition>
</template>
with corresponding css classes but it doesn't work.
I tried that :
<template>
<div class="posts">
<transition-group name="slide-fade">
<div v-for="post in posts" :key="post.id"></div>
</transition-group>
</div>
</template>
but my class .posts is a grid and here I lost the grid behavior.
THE AIM is to animate the entire div .posts rather than each elements of the v-for.
Any idea ?
Thanks all,
I finally achieve this with :
<transition name="slide-fade">
<div :key="posts.length" class="posts"></div>
</transition>
Nothe the :key="posts.length"
The problem is when posts.length doesn't change but it works in a lots of case. I will search how to fix this exception.
If you animate entire div, you should use transition, but in this case all inner elements not animated. If you want to animate all inner elements. You should use transition-group
In your case I think, need use all this method with build-in tag attribute.
Becouse in dock you can read
https://v2.vuejs.org/v2/guide/transitions.html
Unlike transition, it renders an actual element: a span by default. You can change the element that’s rendered with the tag attribute.
So you can write like this(its not full code, you must add name, key and other attrs)
<transition>
<transition-group tag="div" class="posts">
<div v-for="post in posts"></div>
</transition-group>
</transition>

Vue Transition inside the div element doesn't work

Could someone explain me, why the following code doesn't work?
<template>
<div class="modal">
<transition name="slide-in">
<div #click.stop class="modal__container">
<div #click="close" class="modal__button">
<span class="modal__button--close">Close</span>
</div>
</div>
</transition>
<transition name="fade-in">
<div #click="close" class="modal__overlay"/>
</transition>
</div>
</template>
I'm trying to create modal with two different animations (slide-in for text area and fade-in for modal overlay).
If i delete the element with class modal and edit code to the following everything works fine.
<template>
<transition name="slide-in">
<div #click.stop class="modal__container">
<div #click="close" class="modal__button">
<span class="modal__button--close">Close</span>
</div>
</div>
</transition>
</template>
Referencing Vue.js documentation on transitions
Vue provides a variety of ways to apply transition effects when items are inserted, updated, or removed from the DOM
That means that DOM nodes that transition applies classes to, should be those which are inserted/updated/removed.
Since it is a modal window, I assume that it has v-if directive applied in parent component to handle it's visibility. In order for transition to work, it should wrap DOM element that will be updated.
You can understand it more easily if you move code of your modal window into the parent component. Just for better visualization of elements tree and transition's behavior.
In first example, conditional rendering (v-if) applies to <div class="modal">, which is not wrapped with transition - therefore no animation will be triggered. At the same time, nested nodes are wrapped with transition, but there is nothing that will update or remove them. They are statically displayed and inserted initially on component's creation. Nothing to animate.
In order for it to work as expected following structure would be advisable:
<template>
<transition name="fade-in">
<div
class="modal__overlay"
#click="close"
>
<transition name="slide-in">
<div
v-if="containerVisible"
class="modal__container"
#click.stop
>
<div #click="close" class="modal__button">
<span class="modal__button--close">Close</span>
</div>
</div>
</transition>
</div>
</transition>
</template>
This solution expects modal__overlay to have position: fixed; style and variable containerVisible to be set to true inside mounted hook of modal component.

preventing Vue from aggresively reusing dom-elements

Condider the following snippet:
<template v-if="tryIsMobile" >
<div class='device device-mobile-portrait' :class="deviceClass">
<div class="device-scroller-container">
<div class='device-scroller'>
<img id='tryit-img-mobile' :src="srcUrlMobile" v-on:load="onImgLoad" v-on:error="onImgError"/>
</div>
</div>
</div>
</template>
<template v-else>
<div class='device device-tablet-landscape' :class="deviceClass" >
<div class="device-scroller-container">
<div class='device-scroller'>
<img id='tryit-img-tablet' :src="srcUrlTablet" v-on:load="onImgLoad" v-on:error="onImgError"/>
</div>
</div>
</div>
</template>
This code conditionally renders one of the two images. Some user action results in the actual shown image to be toggled.
What I'm seeing is the following: When toggling from say, tryit-img-mobile to tryit-img-tablet, the image loaded as part of tryit-img-mobile will get displayed with different dimensions instantly. However, during the time the image loads it's new source :src="srcUrlTablet", the image with src :src="srcUrlMobile" still displays.
This is probably due to Vue using the same img-tag for both the templates. How can I prevent Vue from doing this, and instead use seperate img-tags?
In cases such as this, Vue uses a special key attribute that tells it not to reuse the same element. Give each element this attribute with a unique value, and Vue will no longer reuse the same element:
<div v-if="tryIsMobile"
class="device device-mobile-portrait"
:class="deviceClass"
key="mobile"
>
...
</div>
<div v-else
class="device device-tablet-landscape"
:class="deviceClass"
key="tablet"
>
...
</div>