ngx-skeleton-loader

NGX Skeleton loader

Why skeletons?

If you want to get more details about that, please read "NGX-Skeleton-Loader — States, Animations, Performance, and Accessibility for your Angular App" blog post at Medium

The idea of this component is make the process transparent and easier. So the main point is integrate this component with other tooling process, such as:

• Server-side rendering;
• Progressive rendering;
• Any other that you like :)

It's totally transparent for you and you can integrate easier in your application, improving your user experience 🎉

• Demo
• Install
• Setup
• Development
• Contribute

Demo

Try out our demos on Stackblitz!

• Usage: animations, appearance, and themes
• User Card Component Loading simulation using NGX Skeleton Loader

Install

You can get it on NPM installing ngx-skeleton-loader module as a project dependency.

npm install ngx-skeleton-loader --save

Setup

You'll need to add NgxSkeletonLoaderModule to your application module. So that, the <ngx-skeleton-loader> components will be accessible in your application.

...
import { NgxSkeletonLoaderModule } from 'ngx-skeleton-loader';
...

@NgModule({
  declarations: [
    YourAppComponent
  ],
  imports: [
    ...
    NgxSkeletonLoaderModule,
    ...
  ],
  providers: [],
  bootstrap: [YourAppComponent]
})

export class YourAppComponent {}

After that, you can use the ngx-skeleton-loader components in your templates, passing the configuration data into the component itself.

• ngx-skeleton-loader: Handle the skeleton animation and the skeleton styles of your app;

<div class="item">
  <ngx-skeleton-loader count="5" appearance="circle"></ngx-skeleton-loader>
</div>

Using NgxSkeletonLoaderModule.forRoot()

Also, you can import the module in your app by calling NgxSkeletonLoaderModule.forRoot() when adding it. So it will be available across your Angular application.

...
import { NgxSkeletonLoaderModule } from 'ngx-skeleton-loader';
...

@NgModule({
  declarations: [
    YourAppComponent
  ],
  imports: [
    ...
    NgxSkeletonLoaderModule.forRoot(),
    ...
  ],
  providers: [],
  bootstrap: [YourAppComponent]
})

export class YourAppComponent {}

<div class="item">
  <ngx-skeleton-loader count="5" appearance="circle"></ngx-skeleton-loader>
</div>

Animations

You can also define which CSS animation you want to use - even not use any, if it's the case - in your skeleton loader by passing the options in your component via [animation] attribute.

Options

• false: it will disable the animation;
• progress - default: it will use it progress as animation;
• progress-dark: it will use it progress-dark as animation. Recommended if your color schema is darken;
• pulse: it will use pulse as animation;

progress is the default animation, used as the single one previously. If you don't pass the animation attribute, it defaults to progress.

<!--
If you need to change all the background wrapper
you need to apply the style changes on the 
`ngx-skeleton-loader` component wrapper
-->
<div class="item">
  <!-- Disables the animation -->
  <ngx-skeleton-loader animation="false"></ngx-skeleton-loader>
  <!-- Uses `progress` as animation -->
  <ngx-skeleton-loader animation="progress"></ngx-skeleton-loader>
  <ngx-skeleton-loader></ngx-skeleton-loader>
  <!-- Uses `pulse` as animation -->
  <ngx-skeleton-loader animation="pulse"></ngx-skeleton-loader>
</div>

You can check the code details in the Stackblitz Live Demo Link

Theming

You can also define different styles for the skeleton loader by passing an object with the css styles - in dashed case - into the component via [theme] attribute.

<!--
If you need to change all the background wrapper
you need to apply the style changes on the 
`ngx-skeleton-loader` component wrapper
-->

<div style="background: #FF0001; padding: 10px;">
  <ngx-skeleton-loader
    count="5"
    [theme]="{ 
      'border-radius': '5px',
      height: '50px',
      'background-color': '#992929',
      border: '1px solid white'
    }"
  ></ngx-skeleton-loader>
</div>

⚠️ This is here only as a documentation, but it's not encouraged to be used. Please consider use it with caution ⚠️

Also, you can use CSS to add theme styles into your component. However, there are some implications:

• You're using :host in your stylesheet, which means you are aware of any possible problem :host can create for your app at that level since it's based on :host DOM style scoping
• You're adding stylesheet based on <ngx-skeleton-loader> internal classes. It means that class naming changes on module's side will be breaking changes for your application as well.

As an example, your Component file is like this

import { Component } from '@angular/core';

@Component({
  selector: 'my-ngx-skeleton-loader-with-theming',
  templateUrl: './my-ngx-skeleton-loader-with-theming.component.html',
  styleUrls: ['./my-ngx-skeleton-loader-with-theming.component.css'],
})
export class MyNGXSkeletonLoaderWithThemingComponent {
  /* ... code goes here*/
}

And your component HTML code is

<!--
file: my-ngx-skeleton-loader-with-theming.component.html

As an example, it's not using themes via [theme] attributes.
-->

<ngx-skeleton-loader count="5" animation="pulse"></ngx-skeleton-loader>

You can apply theme changes in our stylesheet. At the end it will be

/* file: `my-ngx-skeleton-loader-with-theming.component.css`
 *
 * You can find more details about `:host` at
 * Angular Component Style Docs https://angular.io/guide/component-styles#host
 */
:host >>> ngx-skeleton-loader .loader {
  border-radius: 5px;
  height: 50px;
  background-color: #992929;
  border: 1px solid white;
}

You should change the styles on the skeleton wrapper element in case you need to change the background color. You can check the code details in the Stackblitz Live Demo Link or check it out a content load simulation in this Stackblitz Live Demo Link

Development

Run demo locally

1. This project uses Angular CLI as base. That means you just need to run npm start and access the link http://localhost:4200 in your browser

Run tests

1. Run npm test for run tests. In case you want to test using watch, please use npm run tdd

Publish

this project is using np package to publish, which makes things straightforward. EX: np <patch|minor|major> --contents=dist/ngx-skeleton-loader

For more details, please check np package on npmjs.com

Contribute

For any type of contribution, please follow the instructions in CONTRIBUTING.md and read CODE_OF_CONDUCT.md files.

Author

Wilson Mendes (willmendesneto)

• https://twitter.com/willmendesneto
• http://github.com/willmendesneto

Changelog

[2.6.2][] - 2020-12-08

Fixed

• Removing Lighthouse "Avoid non-composited animations" issue. Lighthouse shows warnings from ngx-skeleton-loader.scss -file (progress).

• "Avoid non-composited animations":

• "Animations which are not composited can be janky and contribute to CLS"

To solve that, instead of using CSS background-position the module is now using CSS translate3d, which improves the animation by using GPU instead of CPU. Issue fixed and performance boost added 🎉