How to access elements in a child component <slot>? - javascript

I have a component which uses named slots from <another-component>. I was trying to get the <span> by calling this.shadowRoot.getElementById('title') in <another-component>, it always returns null:
render() {
return html`
<another-component>
<h2 slot="header">
<span id="title"></span>
</h2>
<div slot="footer">
${this.renderFooter()}
</div>
</another-component>
`;
}
Any ideas?

After some digging, i found this is by design. Please correct me if i'm wrong. Basically, you can only access a DOM element under a shadow root where it's defined no matter if it's in a <slot> or not.
For example, let's say in your main component, you have a component A with an element with an ID:
// main component's render
<a>
<p id="title"></p>
</a>
Component A uses component B, and maps its slot content to another slot in component B:
// component A's render
<b>
<p slot="header">blabla</p>
<slot slot="content"></slot>
</b>
Neither A nor B can access the element via shadowRoot.getElementById. Only the main component can get the element by ID.

Related

Angular: render numerous components on (click)

I do not want to render a new component or go to a new route, this is not my intention. I cannot use a single variable with an *ngIf to handle rendering the component as I cannot predict the amount of variables I will need to render.
Here is the situation.
<div ngFor="let stuff of lotsOfStuff">
<div (click)="generateAnotherComponent()">
<span>some basic info</span>
<my-child-component></my-child-component> //component to render on click
</div>
<div (click)="generateAnotherComponent()">
<span>some basic info</span>
<my-child-component></my-child-component> //component to render on click
</div>
</div>
You can generate the component dynamically.
There are various ways to achieve this, but one would be to use a template variable placed on an element, for example
<div #ChildInsertionPoint></div>
And then targeting this "insertion point" as where you'll place the newly generated components by using ViewContainerRef:
#ViewChild('ChildInsertionPoint', { read: ViewContainerRef })
childInsertionPoint: ViewContainerRef;
generateAnotherComponent() {
this.childInsertionPoint.createComponent(ChildComponent);
}
Dynamic component generation became a lot easier with Angular 13 (that's what I've assumed you're using). But if not
Finally, I'm assuming that you will bind your click event to a button instead of the div element itself.
Here's a small example on Stackblitz

Render external element inside Vue component

I have an external div that I need to render inside my Vue app. I'm trying to use a slot, like but that's a no go as nothing renders.
Any ideas?
Goal is to have HTML like this (Vue mounts on #app):
<div id="app" data-slot-header="#header"></div>
<div id="header">
<h1>Title here</h1>
</div>
Then the Vue component
<template>
<div>
<slot name="header"></slot>
</div>
</template>
You can use a dynamic <component> and refer to your #header element as a template reference.
For example
new Vue({
data: () => ({
headerComponent: {
template: '#header' // refer to template element by selector
}
}),
}).$mount('#app')
#app:before,#header:before{position:absolute;top:0;right:0;color:rgba(1,1,1,.5);font-size:.8rem}#app{border:1px solid #666;position:relative}#app:before{content:'Vue app'}#header{position:relative;opacity:.5}#header:before{content:'Original header'}
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.min.js"></script>
<div id="app">
<p>Dynamic component rendered here 👇</p>
<component :is="headerComponent"></component>
</div>
<div id="header">
<h1>Title here</h1>
</div>
Slots are mainly used with reusable Vue components so that the parent component can render custom stuff inside designated sections of the child. The root component does not have a parent, so it doesn't make sense to use slots for this.
Why can't you just hard-code the div in the template? Or do you need it to be dynamic; will you be swapping out the header contents in some situations? Please provide more information about what your use-case is, otherwise my answer is "just hard-code it".
Take a look at portal-vue. It allows child components to render templates anywhere in the DOM. This might work for your situation.

How to pass class attribute to child from parent in vue?

talents. I want to create beautiful button for vue. But I have a problem. I want to pass class attribute to child from parent component easily.
Parent component is like this:
<!-- parent component -->
<template>
<custom-element class="wanted-class">
<span slot="custom-body">
Some Effects or text
</span>
</custom-element>
</template>
and "custom-element" component is
<template>
<div id="custom-element">
Some elements or text
<slot name="custom-body">
Some default text
</slot>
</div>
</template>
<script>
export defatult{ ...
I really want the root element in child ( $("#custom-element") for jQuery expression) to have "wanted-class" from parent. Is it possible? or it's too easy?

How to select content from inner children in ng-content

I have a component called tab which has <ng-content select="[tabItem]"></ng-content>
Sometimes tabItem is inside other child components. My problem is Angular selects the content from direct children, not inner children (app-my-tab), is there any way to do it?
app.component.html
<app-tabs>
<div tabItem>
Tab 1
</div>
<div tabItem>
Tab 2
</div>
<app-my-tab></app-my-tab>
</app-tabs>
my-tab.component.html
<div tabItem>
My Tab
</div>
<div>
Other content
</div>
See this stackblitz
There is no solution for deep selection.
I thing it is logical, because:
understand and real code easily
easy to debug.
If you want really do that use *ngIf in app-my-tab.
To use *ngIF:
All element in app-tabs must have tabItem attribute
send your condition to show/hide some other element in to app-my-tab component. and app-my-tab receive it as #Input() property
in app-my-tab html use *ngIf to show or hide some element
Example: https://stackblitz.com/edit/deep-ng-content-2gyttv?file=src/app/app.component.html

Is there a way to 'pipe-together' slots in nested components in Vue?

Let's say I'm developing an enhanced popper.js for Vue and I'm about to give it some additional functionality. This is how the very (child) component looks like:
<popper>
<div :is="tag" class="popper">
{{ content }}
</div>
<button class="btn btn-primary" slot="reference">
Reference Element
</button>
</popper>
As you can see, for it to work it requires defining reference element right beneath the ".popper" div with a slot="reference" attribute.
Question:
How to turn my enhanced-popper component into a re-usable entity, aka be able to pass slotted data indirectly - from
<enhanced-popper> //referenced element// </enhanced-popper> so that it has the slot="reference" attribute inside the child (popper.js-based) component?
What did not work:
Employing slots and having the attribute in a component passed in by the parent component does not yield desired results, as it does not get rendered at all.
<popper>
<div :is="tag" class="popper">
{{ content }}
</div>
<slot></slot>
</popper>
To ensure having the attribute out there I also tried to replace said button in the child component with a named slot inside a slot and go like this in my enhanced-popper:
<slot name="reference">
<slot></slot>
</slot>
That way the first slotted component has the attribute - and it almost works, but since there are two "slot-layers" (no idea how to call it), the referenced component is not the first one as a child, and popper gets mis-positioned.
Cheers,
Paco

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