We have an in-house Angular component library (one project), each component has basic styling.
We use this library in our App (another project).
A component in the App contains a component from our library.
From the global styles.scss in the App, I can target the elements in the library component just fine.
If I move that global CSS into the App component CSS file, try what may, I cannot target any elements inside the library component.
app-component.html
<div class="outter">
<library-component specificityattr></library-component>
</div>
library-component.html
<div class="generic-styles">
<p class="hello">Hello</p>
</div>
app-component.scss
library-component[specificityattr] p.hello {
background: red;
}
styles.scss
library-component[specificityattr] p.hello {
background: green;
}
Without the selector in styles.scss, I expect the P tag to have a red background.
Only when I put the same selector in styles.scss do I get a green background.
How is this failing?
What is the correct way to style a components sub-components?
Your :host component is th library-component and you want to apply css to some "deep" DOMS so it means :ng-deep
Here is working example
Use
:host library-component[specificityattr] ::ng-deep p.hello {
background: green;
}
What you are experiencing is an effect of the default ViewEncapsulation of components in Angular.
When you define a component such as below, the view encapsulation of the component will be the default value, which I've included inside a comment. This means that Angular won't create a so called 'shadow DOM' for your component, and all the styles will only be applied to your component.
Encapsulated component
#Component({
selector: 'my-component',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css'],
//encapsulation: ViewEncapsulation.Emulated
})
If you instead want to apply the styles not only to your component, you can specify a specific ViewEncapsulation in your component declaration. Using ViewEncapsulation.None will move the styles to the DOM head, and it will still not create a shadow DOM.
Without encapsulation
#Component({
selector: 'my-component',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css'],
encapsulation: ViewEncapsulation.None
})
Have a look at this StackBlitz example
It's important to keep in mind that ViewEncapsulation.None will "leak" your styles to other components, which in turn will make it harder to style your application unless you know exactly where your styles are defined.
Related
I have some issue with my Angular web component.
My angular application contains the web component as a child, but the issue is the css of the child component is also applying to its parent.
For instance, in web component, there's some style on its body tag. However, it is also overriding the style of its parent. Is there any way to avoid this?
<div id="my-app">
<webcomponent></webcomponent>
</div>
If you have built your webcomponent with Angular Elements, you can make use of dom / style isolation by setting ViewEncapsulation to ShadowDom:
import { Component, ViewEncapsulation } from "#angular/core";
#Component({
selector: "webcomponent",
template: `
<h3>Webcomponent</h3>
`,
styleUrls: ["./webcomponent.css"],
encapsulation: ViewEncapsulation.ShadowDom
})
export class WebcomponentComponent {}
Please notice that by using shadow dom, you will also not be able to style html inside the component from outside the component.
I've used :host ::ng-deep successfully to achieve what you're looking for.
For the CSS inside web component, add :host ::ng-deep prior to your CSS element. Ex: :host ::ng-deep .my-class { color: blue }
From the docs, 'In order to scope the specified style to the current component and all its descendants, be sure to include the :host selector before ::ng-deep'
Docs: https://angular.io/guide/component-styles#deprecated-deep--and-ng-deep
I have created a new Angular CLI project and a component where I have tried work on css specificity. Wherewer I tryed, class styles overwrite tag styles, but only on Angular project it's working vise versa
I have founded that ViewEncapsulation.None makes the css styles show darkgreen backgound-color and with the angular default view encapsulation (ViewEncapsulation.Emulated) browser shows aqua background-color.
component code
import { Component, OnInit } from '#angular/core';
import {ToastrService} from "ngx-toastr";
//import {ViewEncapsulation} from "#angular/cli/lib/config/schema";
#Component({
selector: 'app-toastr',
templateUrl: './toastr.component.html',
styleUrls: ['./toastr.component.css'],
//encapsulation: ViewEncapsulation.None
})
html code
<div>
<div class="myspan">
something
</div>
</div>
and styles
div div{
background-color: aqua;
}
.myspan {
background-color: darkgreen;
}
I expect to receive an answer why it works differently
FYI
ViewEncapsulation.Emulated: Any styles we define on a component don’t leak out to the rest of the application. But, the component still inherits global styles like twitter bootstrap.
ViewEncapsulation.Native: Styles we set on a component do not leak outside of the components scope. Component is also isolated from the global styles we’ve defined for our application.
ViewEncapsulation.None: We are not encapsulating anything, the style we defined in our component has leaked out and started affecting the other components.
I ran into an issue using Angular Material Design where I need to use ng-deep in order to adjust the styling of an accordion. However, I am using an accordion elsewhere and it is grabbing the same styles. This is not desired.
Is it supposed to do that? How do I fix it?
ng-deep is deprecated, and support is being removed from major browsers. You can read more about it in the Angular Docs.
I would suggest you to remove the view encapsulation from the component instead (None removes style encapsulation for that component, so you can target Angular Material styles).
import { ViewEncapsulation } from '#angular/core';
#Component({
selector: 'app-example-component',
templateUrl: './example.component.html',
styleUrls: ['./example.component.scss'],
encapsulation: ViewEncapsulation.None
})
I found that in order to keep the styles limited to the component, I had to encapsulate the ::ng-deep code with :host like so:
:host {
::ng-deep {
/* ... custom styles here */
}
}
I Have two menus in my app.
Both of them are using primeng Panel Menu
I have changed their css.
The problem is now after adding the second-menu to my app, left-menu's style has changed.
I tried to use View encapsulation on both of them, the left-menu style still not encapsulated
Here's the first menu header
#Component({
selector: 'app-left-menu',
templateUrl: './left-menu.component.html',
styleUrls: ['./left-menu.component.css'],
encapsulation: ViewEncapsulation.Emulated
})
Second menu
#Component({
selector: 'app-second-menu',
templateUrl: './second-menu.component.html',
styleUrls: ['./second-menu.component.css'],
encapsulation: ViewEncapsulation.Emulated
})
In my CSS I use ng-deep and :host
here's an example
:host ::ng-deep .ui-panelmenu-header.ui-state-default:hover {
background-color: #555555;
}
Here's a stackblitz example
I won't add all the CSS because it's the same on both styles
Using only ::ng-deep will affect all the classes in the project even if not children of the component where the css is declared. (here is a simple stackblitz reproduting this behavior)
If you want to affect only child elements of the component but not the elements on the same level, you should use :host with the ::ng-deep.
Here is a fork of your stackblitz with a fix suggestion.
Is there a way to stop global styles to bleed in to child components without ViewEncapsulation.Native?
For example I have a global style
.container {
background: green
}
and a component
#Component({
template: html,
styleUrls: [url],
selector: 'dynamic-lp',
encapsulation: ViewEncapsulation.Emulated
})
The component is a dynamically added component with variable styleUrls and template html, so I don't want to inherit the green background if the template has a .container class.
If I change ViewEncapsulation.Emulated to ViewEncapsulation.Native all works as expected, but I would like to know if there's another way to achieve what I want since Shadow Dom is not supported by most browsers yet
UPDATE
I've found a solution which is working for me.
Wrap your sass imports in a "body:not(...)" assignment like this
body *:not(.innerhtml-container) {
#import 'bootstrap';
#import 'someother-plugin';
/* Components */
#import 'components/loading-bar';
#import 'components/textfield';
}
And add a container class "innerhtml-container" around the component template.
For example:
<div class="innerhtml-container"><div class="container">...</div></div>
this way no css inheritance will be passed on to the child component