vuejs: How to change the class of each item in v-for - class

My component template have an img
<img src="img/loading.gif" :data-src="url" class="live-snapshot-img" :class="{lazy:true, 'lazy-loaded': false}">
When it rendered, I'll trigger out the lazy event. The class will changed to 'lazy-loaded' from 'lazy'.
<img src="img/loading.gif" :data-src="url" class="live-snapshot-img lazy-loaded">
Then if the data changed, I want the class change back to 'lazy'. The bind:class doesn't work.

My solution is
Create a method in component
lazyload: function() {
var clazz = {lazy: true, 'lazy-loaded': false}
clazz['dummy' + Math.random()] = true
return clazz
},
and change the img to
<img src="img/loading.gif" :data-src="url" class="live-snapshot-img" :class="lazyload()">

I think you're approaching this in slightly the wrong way. You have the right idea, but I feel like your thinking and jQuery post render dom manipulation manner, not that this is bad, just not right for this situation. Vue works a little differently. If you want to change the class after the event in this particular instance, you bind your :class to a variable in your vue component.
If I wanted to make this happen, I would probably start by setting a variables in my component data for the state. (see: Class and Style Bindings)
Vue.component('my-component-name', {
data: function () {
return {
imageState: {'lazy': true, 'lazy-loaded': false}
}
}
})
Then bind that to your element:
<img src="img/loading.gif" :data-src="url" class="live-snapshot-img" :class="imageState">
You can then manipulate the imageState in your component methods in any way you want.

Related

Using a Vue3 component as a Leaflet popup

This previous SO question shows how we can use a Vue2 component as the content of a LeafletJS popup. I've been unable to get this working with Vue3.
Extracting the relevant section of my code, I have:
<script setup lang="ts">
import { ref } from 'vue'
import L, { type Content } from 'leaflet'
import type { FeatureCollection, Feature } from 'geojson'
import LeafletPopup from '#/components/LeafletPopup.vue'
// This ref will be matched by Vue to the element with the same ref name
const popupDialogElement = ref(null)
function addFeaturePopup(feature:Feature, layer:L.GeoJSON) {
if (popupDialogElement?.value !== null) {
const content:Content = popupDialogElement.value as HTMLElement
layer.bindPopup(() => content.$el)
}
}
</script>
<template>
<div class="map-container">
<section id="map">
</section>
<leaflet-popup ref="popupDialogElement" v-show="false">
</leaflet-popup>
</div>
</template>
This does produce a popup when I click on the map, but it has no content.
If, instead, I change line 14 to:
layer.bindPopup(() => content.$el.innerHTML)
then I do get a popup with the HTML markup I expect, but unsurprisingly I lose all of the Vue behaviours I need (event handling, etc).
Inspecting the addFeaturePopup function in the JS debugger, the content does seem to be an instance of HTMLElement, so I'm not sure why it's not working to pass it to Leaflet's bindPopup method. I assume this has something to do with how Vue3 handles references, but as yet I can't see a way around it.
Update 2022-06-09
As requested, here's the console.log output: I've put it in a gist as it's quite long
So just to document the solution I ended up using, I needed to add an additional style rule in addition to the general skeleton outlined in the question:
<style>
.leaflet-popup-content >* {
display: block !important;
}
</style>
This overrides the display:none that is attached to the DOM node by v-show=false. It would be nice not to need the !important, but I wasn't able to make the rule selective enough in my experiments.

How to seperate Vue logic in a laravel app based on layout and page templates

I have a laravel app and a Vue instance attached to the body (or a div, just inside the body).
const app = new Vue({
el: '#app'
});
I think it makes sense to use the Vue instance for stuff relating to the layout (eg header, nav, footer logic).
Now I have a form that is visible on a specific route (e.g. example.com/thing/create). I want to add some logic to it, e.g. hiding a field based on selected option in the form. It is logic meant for just this form (not to be reused). I prefer not to put all the logic inline with the form but put it in the app.js. I could put it in the Vue instance bound to the body but that sounds odd as it only applies to the form that is much deeper into the dom.
I want to leave the markup of the form in the blade template (that inherits the layout).
I tried creating a component but am not sure how to bind this inside the main Vue instance. What is the best way to handle things for this form, put it in the app.js and have it somewhat structured, putting the variables somewhat into scope. Or is it really necessary to remove the main Vue instance bound to the full layout code?
What I tried was something like this, but it does not work (attaching it to the <form id="object-form"> seems to fail:
var ObjectForm = {
template: function() { return '#object-form'},
data: function() {
return {
selectedOption: 1
}
},
computed: {
displayField: function() {
// return true or false depending on form state
return true;
}
}
};
Things do work if I remove the #app Vue instance or when I put everything directly in the app Vue instance. But that seems messy, if I have similar variables for another form they should be seperated somewhat.
I would appreciate some advice regarding the structure (differentiate page layout and page specific forms) and if possible some example to put the form logic inside the main app.js.
I hope this helps kind of break things down for you and helps you understand Vue templating.
It is best to take advantage of Vue's components. For you it would look something like this. Some of this code depends on your file structure, but you should be able to understand it.
In your app.js file (or your main js file)
Vue.component('myform',require('./components/MyForm.vue'));
const app = new Vue({
el: "#app"
});
Then create the MyForm.vue file
<template>
<form>
Put Your Form Markup Here
</form>
</template>
<script>
// Here is where you would handle the form scripts.
// Use methods, props, data to help set up your component
module.exports = {
data: function() {
return {
selectedOption: 1
}
},
computed: {
displayField: function() {
// return true or false depending on form state
return true;
}
},
methods: {
// add methods for dynamically changing form values
}
}
</script>
Then you will be able to just call in your blade file.
<myform></myform>
I found out how to do it. The trick was to use an inline template. Surround the form in the view with:
<object-form inline-template>
<form>...</form>
</object-form>
Where object-form is the name of the component. In the ObjectForm code above I remove the template, like this:
var ObjectForm = {
data: function() {
return {
selectedOption: 1
}
},
computed: {
displayField: function() {
// return true or false depending on form state
return true;
}
}
};
I attach the component within the root vue app like this:
const app = new Vue({
el: 'body',
components: {
'object-form': ObjectForm
}
});
This way I can use the form as it was generated from the controller and view and I can separate it from the root (attached to body) methods and properties.
To organize it even better I can probably store the ObjectForm in a seperate .vue file the way #Tayler Foster suggested.

ClipboardJS with React, using document.getElementById()

Originally, I had it working fine.
Then I did this and now I can't get it to work
ClipboardField.js
import React from 'react';
export default (props) => {
return(
<div id="clip" data-clipboard-text={props.code} onClick={props.onClick}>
<p> Copy to clipboard.</p>
</div>
);
}
Field.js
class DashWizardTwoCore extends Component {
componentDidMount(){
const btns = document.getElementById('clip');
const clipboard = new Clipboard(btns);
}
componentDidUpdate() {
clipboard.on('success', function(e) {
console.log(e);
});
clipboard.on('error', function(e) {
console.log(e);
});
}
render(){
const someCode = "const foo = 1"
return (
<div>
<ClipboardField code={this.someCode} /> }
</div>
);
}
}
If you take the code out of ClipboardField and into Field it works. It's mostly, how do I use document.getElementById() in my parent component to find something in my child?
Their examples:
https://github.com/zenorocha/clipboard.js/blob/master/demo/constructor-selector.html#L18
https://github.com/zenorocha/clipboard.js/blob/master/demo/constructor-node.html#L16-L17
https://github.com/zenorocha/clipboard.js/blob/master/demo/constructor-nodelist.html#L18-L19
Your code is fine you just have a few issues:
you are binding clipboard.on in componentDidUpdate which won't trigger here since you are not really changing anything (in the ClipboardField component) that triggers this event.
You are passing {this.someCode} in the code prop which would be undefined should just be {someCode}
So it's just a matter of moving your clipboard.on to the componentDidMount right after the new Clipboard and use code={someCode}
https://jsfiddle.net/yy8cybLq/
--
In React whenever you want to access the actual dom element of your component we use what react calls as refs, I would suggest you do this rather than using getElementById as this is the "best practice".
However stateless components (like your ClipboardField component above) can't have refs so you just need to change it to be a normal component.
Here's a fiddle with your code but using refs instead: https://jsfiddle.net/e5wqk2a2/
I tried including links to the react docs for stateless components and refs but apparently don't have enough "rep" to post more than 2 links, anyways quick google search should point you in the right direction.
I adjusted your code and created a simple integration of clipboard.js with React.
Here's the fiddle: https://jsfiddle.net/mrlew/ehrbvkc1/13/ . Check it out.

Is it fine to mutate attributes of React-controlled DOM elements directly?

I'd like to use headroom.js with React. Headroom.js docs say:
At it's most basic headroom.js simply adds and removes CSS classes from an element in response to a scroll event.
Would it be fine to use it directly with elements controlled by React? I know that React fails badly when the DOM structure is mutated, but modifying just attributes should be fine. Is this really so? Could you show me some place in official documentation saying that it's recommended or not?
Side note: I know about react-headroom, but I'd like to use the original headroom.js instead.
EDIT: I just tried it, and it seems to work. I still don't know if it will be a good idea on the long run.
If React tries to reconcile any of the attributes you change, things will break. Here's an example:
class Application extends React.Component {
constructor() {
super();
this.state = {
classes: ["blue", "bold"]
}
}
componentDidMount() {
setTimeout(() => {
console.log("modifying state");
this.setState({
classes: this.state.classes.concat(["big"])
});
}, 2000)
}
render() {
return (
<div id="test" className={this.state.classes.join(" ")}>Hello!</div>
)
}
}
ReactDOM.render(<Application />, document.getElementById("app"), () => {
setTimeout(() => {
console.log("Adding a class manually");
const el = document.getElementById("test");
if (el.classList)
el.classList.add("grayBg");
else
el.className += ' grayBg';
}, 1000)
});
And here's the demo: https://jsbin.com/fadubo/edit?js,output
We start off with a component that has the classes blue and bold based on its state. After a second, we add the grayBg class without using React. After another second, the component sets its state so that the component has the classes blue, bold, and big, and the grayBg class is lost.
Since the DOM reconciliation strategy is a black box, it's difficult to say, "Okay, my use case will work as long as React doesn't define any classes." For example, React might decide it's better to use innerHTML to apply a large list of changes rather than setting attributes individually.
In general, if you need to do manual DOM manipulation of a React component, the best strategy is to wrap the manual operation or plugin in its own component that it can 100% control. See this post on Wrapping DOM Libs for one such example.

Create jQuery ui resizable instance using selector added to DOM by jQuery

I'm trying to start a jquery ui resizable instance, but using a selector added to the DOM by jquery itself. This is a basic example of my script:
HTML:
<div class='lyr'></div>
jQuery:
// Add class
$('lyr').addClass('fixed');
// Resizable
$('.fixed').resizable({
aspectRatio: true,
handles: 'all'
});
I've thought about using something along the lines of live() or bind() but I have no event to bind to. Any help appreciated.
I have used the LiveQuery plugin - http://brandonaaron.net/code/livequery/docs in the past to be able to target elements added to the dom, like in your case.
If I've got this right, you want anything on the page which has the class "fixed" to be resizable, even if the class is added after the page has loaded? You're right that live, bind and delegate won't help here.
I can think of two possibilities, neither lovely.
First, set up a live "mouseenter" event which will make the element resizable if it wasn't before:
$(body).delegate(".fixed", "mouseenter", function(ev) {
var target = $(ev.target);
if (target.data("resizable")) return;
target.resizable({
aspectRatio: true,
handles: 'all'
});
})
This gets us round the problem of having no event to bind to.
Alternatively, you could monkeypatch jQuery.fn.addClass:
var classRe = new RegExp(c + className + \b);
._addClass = jQuery.fn.addClass;
jQuery.fn.addClass = function(className) {
if (classRe.test(classname)) {
if (this.data("resizable")) return;
this.resizable({
aspectRatio: true,
handles: 'all'
});
}
jQuery.fn._addClass.apply(this, arguments);
}
Of course this will only work if the class is added through the addClass method.
Also in your example,
$('lyr').addClass('fixed');
Should probably be:
$('.lyr').addClass('fixed');