Confusion regarding DOM manipulation in VueJs - vuejs2

I have a select element in my template and I'm calling a function with #change.
<select
#change="updatePriorityAndStatus($event, windex, w.ProjectCode)">
</select>
As you can see I'm using the $event variable to access the DOM event.
Now inside my function if I do something likes this
updatePriorityAndStatus($event, id, code) {
$event.target.parentNode.children[0].style.backgroundColor = '#ff3300';
},
Does it manipulate the actual DOM ?
As we know we are not supposed to manipulate the actual DOM like we do in JS or JQuery.

Related

Convert from jQuery to Vue?

I would like to transform the following code which is in javascript:
$('a').click(function() {
$(this).find('i').toggleClass('fa-heartbeat');
});
in vue.js.
function name: like
javascript test: https://jsfiddle.net/jsk590ep/
In Vue, you typically don't select and manipulate DOM elements directly, you rather bind data to parts of the markup within your Vue components.
That said: You don't even need a function for that.
Simply
add a data element that indicates which state the icon is in (see https://v2.vuejs.org/v2/guide/#Declarative-Rendering)
change its value in the #click handler of the surrounding a, see https://v2.vuejs.org/v2/guide/events.html#Listening-to-Events
conditionally bind the fa classes based on the state to the icon, see https://v2.vuejs.org/v2/guide/class-and-style.html
<a href="#" #click="liked = !liked">
<i :class="['fa', liked ? 'fa-heartbeat' : 'fa-plus-circle']"></i>
</a>
When looking at the vue docs, note that #click in the example is a shortcut for v-on:click and :class for v-bind:class.
Working example here: https://codesandbox.io/s/stack-overflow-q-57403395-ul62e?module=/src/App.vue

Problem with creating a div into the document (DOM)

I have some problems with this fragment, it creates a div into the DOM so that div appears in every page as it is normal, which is an image.
How can I change it so this div is only being created when I access at this custom component (Model.vue) and no longer being visible once I'm out of the component page.
Thanks!!
container = document.createElement( 'div' );
document.body.appendChild( container );
If your HTML is predictable you should probably add it in your template (as HTML or as a component) and then show/hide it with v-if or v-show
If you need static content, for example depending on the user input, then v-html is the way.
If you need dynamic content (e.g. with event bindings), then check out render functions.
There's also dynamic component like <component :is="someComponent">, where someComponent can be either a string name of the component, or the component itself. But you should probably try the other solution first.
First of all direct DOM manipulation(Add/Del elements) is not at all preferred in vuejs. You can use v-if instead to show the element conditionally.
Or else if you still want to do direct manipulation then you can write the above lines of code in mounted hook of your model.vue component.
mounted() {
container = document.createElement('div');
container.setAttribute("id", "divId");
}
And then in before destroyed hook you can remove this element from the DOM as below.
beforeDestroy() {
var elem = document.querySelector('#divId');
elem.parentNode.removeChild(elem);
}

Access HTML of DOM element?

With Vue 2 I have this in my template:
<table ref="test">
....
</table>
When I get this via this.$refs.test I get [object HTMLTableElement] is there a way to return the actual HTML?
It's hard to tell what's your purpose in doing this, but if you want to be able to for example display it's outerHTML you have to check if this.$refs.test exists and if it does - render it. This is because refs aren't reactive so using computed properties won't work.
<pre v-if="!!$refs.test">{{$refs.test.outerHTML}}</pre>
If you want to set it's outerHTML to a property or use querySelector or any other DOM operation on it, you need to wait for your component to be mounted.
mounted() {
this.testRowContent = this.$refs.test.querySelector('.test').innerHTML;
}
Example: http://jsfiddle.net/eywraw8t/323125/

VueJS find element by key

I've just wanted to know if it is possible to find a DOM element by the key attribute of vue?
I'm currently working with a list. I'm displaying it via v-for directive on a div. I'm binding the key with the index of the elements.
v-for="(apk, index) in project.apks" v-bind:key="index"
It would really help me if i could compute something for each of these elements as soon as they are fetch from my server and displayed. It's just parsing a file and looking for keyword, and accordingly choosing a css class for the items.
The problem is I dont know how to call a method for each of these elements as soon as they are added to the DOM. They are a lot of html events but i couldnt find one representing the object beeing inserted to dom :(
The purpose of key is not selecting element. Even if it can be done, don't do it.
The proper way to do it is by using ref.
for example, add ref attribute to your html like this
v-for="(apk, index) in project.apks" v-bind:key="index" :ref="'sample-ref-'+index"
and then in your methods, you can get the DOM using this.$refs['sample-ref-0'],this.$refs['sample-ref-1'] and so on.
Hope this helps.
I found that if you give the 'ref' the same name in a v-for, like this:
<div v-for="data in list" :key="data.id" ref="bar"></div>
Then you will find they just store in an array called 'bar' and you can visit them by:
this.$refs['bar'][index]
something like this could allow you to find a component by key :
this.$children.forEach(child=>{
print("child.$vnode.key")
})
also use mounted , as it gets called when the component is added to the dom:
mounted:function(){
this.$el.querySelector("#ele1")...
}
The problem is I dont know how to call a method for each of these elements as soon as they are added to the DOM. They are a lot of html events but i couldnt find one representing the object beeing inserted to dom :(
You can create a new component with your v-for and just call the created() hook.
Example
/* On your main function */
<div v-for="apk in project.apks">
<apk :data="apk"></apk>
</div>
/* On your 'apk' component */
export default {
props: [ "data" ],
created() {
console.log("Created !");
}
}

Access v-for model used within Vue 2 custom directive

Question
How can I update the model data used within a Vue 2 custom directive?
Setup:
<ul>
<li v-for="item in items">
<select my-directive="item">...</select>
</li>
</ul>
So let's say I have a directive with a hook like this:
Vue.directive('chosenjs', {
inserted: function (el, binding, vnode) {
// Here, I'm setting up a callback with the jQuery Chosen library, but this could be any callback.
jQuery(el).chosen().change(function(event, change) {
// CODE HERE...
});
}
});
In the CODE HERE... section, if binding.value is a pointer (array/object), then this is straight-forward. For example, for an array, I'd do e.g. binding.value.push(someValue), and Vue's observable will handle it. But if the value is a primitive, then what can be done?
If the directive is not used within a v-for loop, you can use the vnode to modify the data in the component. It works great as I show here.
But if it is in a v-for, it seems there's no way. Even with access to the binding.expression, there's no way to get at the v-for item.
Background
I'm trying to work with Vue and the ChosenJS jQuery library. I got most of the way there with this answer, but there is a bug when the directive is used within a v-for loop.