Angular

Loading Components Dynamically in Angular 9 with Ivy

Published Mar 27, 2020

Updated Feb 14, 2023

5 min read

This article was written over 18 months ago and may contain information that is out of date. Some content may be relevant but please refer to the relevant official documentation or available resources for the latest information.

Loading Components Dynamically in Angular 9 with Ivy

This article will show you how to start loading components dynamically using Angular 9 with Ivy. This is not exactly new and exclusive to Angular 9, but now we can have components without a module, and by making them load dynamically, we get the benefits of lazy loading.

Making the story short, we'll reduce the main bundle size by loading only the components we need.

Imagine you have a huge module that consists of multiple components. Every user has unique needs, meaning that they will only use a subset of all the available components. The goal of this article is to explore a possible solution for addressing it.

To make it easier, I decided to work on a use case that I know.

If you want to skip ahead, and go straight to the code, I created this repository with the finished version of the app. It looks like this:

The Problem

Let's say that we have this application, with which users can log in and perform some actions. Regardless of whether the user is a guest, or a registered user, they both have a profile page. Each kind of user has different actions that they can perform.

Solution

One way to solve this problem would be to use conditionals with the help of the ngIf structural directive. This allows us to have a different layout for each. It works, but is it the best solution? Remember that now both users have to download the entire component and actions, whether or not they use them.

I want to clarify, I have used the ngIf strategy in applications that have been in production for years.

Let's do something different this time. Let's create a component for each kind of user, and dynamically load them. This way, the main bundle won't have any of them, and they will be downloaded on demand.

Implementation

It's time to have fun. Before we start, make sure you have installed the Angular CLI v9. If you need help on this step, just drop a comment below. Once you have the right version of the Angular CLI installed, follow these steps:

Open your terminal of choice.
Run the command ng new {your-app-name}
Open the new project in your editor of choice.

Let's start with the loading of components. We are going to create a new service AppService. Once you've created it, open it in your editor src/app/app.service.ts and paste this:

import {
  Injectable,
  ComponentFactoryResolver,
  ViewContainerRef
} from '@angular/core';
import { from } from 'rxjs';
import { map } from 'rxjs/operators';

export interface ComponentLoader {
  loadChildren: () => Promise<any>;
}

@Injectable({
  providedIn: 'root'
})
export class AppService {
  constructor(private cfr: ComponentFactoryResolver) {}

  forChild(vcr: ViewContainerRef, cl: ComponentLoader) {
    return from(cl.loadChildren()).pipe(
      map((component: any) => this.cfr.resolveComponentFactory(component)),
      map(componentFactory => vcr.createComponent(componentFactory))
    );
  }
}

At first glance, you see ComponentFactoryResolver, ViewContainerRef, ComponentLoader, and think:

What kind of sorcery is this?

It's simpler than you think. It's just that there are a few new things. We are injecting the ComponentFactoryResolver, which, given a Component, returns a Factory that can be used to create new instances of it. The ViewContainerRef is a pointer to an element in which we are going to insert the newly instantiated component. The ComponentLoader is a simple interface. It holds a loadChildren function that returns a Promise. This promise, once resolved, returns a Component.

And finally, we are just putting everything together. Using the from function from rxjs, I'm able to transform the promise into an observable. Then, I'm mapping this component into a factory, and finally I will inject the component, and return the instance.

Now, let's create another service named ProfileService that will use the AppService to load the respective component. It also holds the loggedIn state. Create a file in src/app/profile/profile.service.ts:

import { Injectable, ViewContainerRef } from '@angular/core';
import { BehaviorSubject } from 'rxjs';
import { AppService } from '../app.service';

@Injectable({ providedIn: 'root' })
export class ProfileService {
  private isLoggedIn = new BehaviorSubject(false);
  isLoggedIn$ = this.isLoggedIn.asObservable();

  constructor(private appService: AppService) {}

  private guestProfile() {
    return () =>
      import('./guest-profile/guest-profile.component').then(
        m => m.GuestProfileComponent
      );
  }

  private clientProfile() {
    return () =>
      import('./client-profile/client-profile.component').then(
        m => m.ClientProfileComponent
      );
  }

  login() {
    this.isLoggedIn.next(true);
  }

  logout() {
    this.isLoggedIn.next(false);
  }

  loadComponent(vcr: ViewContainerRef, isLoggedIn: boolean) {
    vcr.clear();

    return this.appService.forChild(vcr, {
      loadChildren: isLoggedIn ? this.clientProfile() : this.guestProfile()
    });
  }
}

This service is way easier to understand. We created a Subject to manage the isLoggedIn state, and two methods to many events into the subject. We created two private methods that return a function that returns a Promise of a Component.

Yes, just like the ComponentLoader interface.

And finally, a magical method: loadComponent takes a ViewContainerRef and the isLoggedIn state. Clears the ViewContainerRef, emptying it entirely. Then, it calls the forChild method from AppService with the ViewContainerRef we just cleaned, and for the ComponentLoader, it has a ternary expression that determines which Component to load.

In order to make the loading of the components easier, we are going to create a directive that will help with that. Create a file src/app/profile/profile-host.directive.ts:

import { Directive, ViewContainerRef } from '@angular/core';

@Directive({ selector: '[appProfileHost]' })
export class ProfileHostDirective {
  constructor(public viewContainerRef: ViewContainerRef) {}
}

This is just a trick to make it easier to get the ViewContainerRef we're looking for. Now create a file src/app/profile/profile.component.ts:

import { Component, OnInit, OnDestroy, ViewChild } from '@angular/core';
import { ProfileHostDirective } from './profile-host.directive';
import { ProfileService } from './profile.service';
import { mergeMap, takeUntil } from 'rxjs/operators';
import { Subject } from 'rxjs';

@Component({
  selector: 'app-profile-container',
  template: `
    <ng-template appProfileHost></ng-template>
  `
})
export class ProfileComponent implements OnInit, OnDestroy {
  @ViewChild(ProfileHostDirective, { static: true })
  profileHost: ProfileHostDirective;
  private destroySubject = new Subject();

  constructor(private profileService: ProfileService) {}

  ngOnInit() {
    const viewContainerRef = this.profileHost.viewContainerRef;

    this.profileService.isLoggedIn$
      .pipe(
        takeUntil(this.destroySubject),
        mergeMap(isLoggedIn =>
          this.profileService.loadComponent(viewContainerRef, isLoggedIn)
        )
      )
      .subscribe();
  }

  ngOnDestroy() {
    this.destroySubject.next();
    this.destroySubject.complete();
  }
}

All we are doing here is creating a simple ng-template in which we attach the ProfileHostDirective, so we can use the ViewChild decorator, and get the viewContainerRef. OnInit we are getting the viewContainerRef, and using the isLoggedIn$ observable from ProfileService to know everytime the isLoggedIn state changes. Then, using the mergeMap operator, I call the loadComponent function that is doing the real magic.

If you take a look at src/app/profile/profile.service.ts, you'll notice I'm referencing a GuestProfileComponent, and a ClientProfileComponent. Now it's time to create them.

First, go to the src/styles.scss, and include this:

html,
body {
  margin: 0;
  padding: 0;
}

To make the styling easier, I created a folder style inside the assets folder, in which I have 2 scss files:

_variables.scss
_mixins.scss

They hold all the shared styles, to make everything easier to maintain:

// _variables.scss
$card-width: 400px;
$avatar-width: 80px;
$container-margin: 20px;

// _mixins.scss
@import './variables.scss';

@mixin button($color) {
  display: inline-block;
  padding: 0.5rem 1rem;
  border: 1px solid $color;
  border-bottom-color: darken($color, 10);
  border-radius: 5px;
  background: linear-gradient(180deg, $color, darken($color, 10));
  color: white;
  cursor: pointer;
  font-family: Arial, Helvetica, sans-serif;
  box-shadow: 1px 2px 4px rgba(0, 0, 0, 0.2);
  font-size: 1rem;

  &:hover {
    background: $color;
    box-shadow: 1px 4px 6px rgba(0, 0, 0, 0.2);
  }

  &:active {
    background: darken($color, 10);
  }
}

@mixin card {
  box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2);
  border: 1px solid #eee;
  width: $card-width;
  padding: 1rem;
}

I also created a folder images, and included an image named profile.png. You can have any image as long as it's a square.

Let's create the GuestProfileComponent. For this, we'll need three files; a template, a stylesheet, and a typescript file. Let's start with the template: create a file src/app/profile/guest-profile/guest-profile.component.html

<section class="card">
  <div class="card__avatar">
    <div class="card__avatar__head"></div>
    <div class="card__avatar__body"></div>
  </div>

  <div class="container">
    <h2 class="card__title">Guest Profile</h2>

    <p class="card__subtitle">
      Thank you for visiting us. If you want to take your experience to the next
      level, all you need is to log in.
    </p>

    <div class="card__toolbar">
      <button (click)="login()">Login</button>
    </div>
  </div>
</section>

Now let's create the stylesheet in src/app/profile/guest-profile/guest-profile.component.scss:

@import '~src/assets/styles/mixins.scss';

.card {
  display: flex;
  @include card();

  &__title {
    margin: 0 0 0.5rem 0;
  }

  &__subtitle {
    margin: 0 0 0.5rem 0;
  }

  &__toolbar button {
    @include button(#145092);
  }

  &__avatar {
    height: 80px;
    width: $avatar-width;
    border: 2px solid #bbb;
    background: #666;
    position: relative;
    overflow: hidden;

    &__head {
      position: absolute;
      border-radius: 50%;
      background: #bbb;
      width: 35px;
      height: 35px;
      top: 15px;
      left: 22px;
    }

    &__body {
      position: absolute;
      border-radius: 50%;
      background: #bbb;
      width: 70px;
      height: 50px;
      top: 55px;
      left: 5px;
    }
  }
}

.container {
  width: $card-width - $avatar-width - $container-margin;
  margin: 0 $container-margin;
}

And finally, the typescript file in src/app/profile/guest-profile/guest-profile.component.ts:

import { Component } from '@angular/core';
import { ProfileService } from '../profile.service';

@Component({
  selector: 'app-guest-profile',
  templateUrl: './guest-profile.component.html',
  styleUrls: ['./guest-profile.component.scss']
})
export class GuestProfileComponent {
  constructor(private profileService: ProfileService) {}

  login() {
    this.profileService.login();
  }
}

That's great! All we need to do now is create the ClientProfileComponent. We'll need the same files from the GuestProfileComponent. Let's start with the template src/app/profile/client-profile/client-profile.component.html

<section class="card">
  <figure class="card__avatar">
    <img src="assets/images/profile.png" />
  </figure>

  <h2 class="card__title" contenteditable="true">Daniel Marin</h2>

  <p class="card__subtitle" contenteditable="true">
    Senior Software Engineer at This Dot Labs, a company specializing in Modern
    Web Technologies, designing, and developing software to help companies
    maximize efficiency in their processes.
  </p>

  <div class="card__toolbar">
    <button (click)="logout()">Logout</button>
  </div>
</section>

Now, let's create the stylesheet in src/app/profile/client-profile/client-profile.component.scss:

@import '~src/assets/styles/mixins.scss';

.card {
  @include card();

  &__avatar {
    height: $avatar-width;
    width: $avatar-width;
    margin: 0 auto;
    border-radius: 50%;
    overflow: hidden;

    img {
      width: 100%;
      height: 100%;
      object-fit: cover;
    }
  }

  &__title {
    margin: 1rem 0 0.5rem 0;
    text-align: center;
  }

  &__subtitle {
    margin: 0 0 1rem 0;
    text-align: center;
  }

  &__toolbar {
    display: flex;
    justify-content: center;

    button {
      @include button(#a80000);
    }
  }
}

And finally, the typescript file in src/app/profile/client-profile/client-profile.component.ts:

import { Component } from '@angular/core';
import { ProfileService } from '../profile.service';

@Component({
  selector: 'app-client-profile',
  templateUrl: './client-profile.component.html',
  styleUrls: ['./client-profile.component.scss']
})
export class ClientProfileComponent {
  constructor(private profileService: ProfileService) {}

  logout() {
    this.profileService.logout();
  }
}

Now, all we have to do is update the AppComponent. Go to src/app/app.component.html, remove all its content, and put this instead:

<h1 class="header">Dynamic components</h1>
<main class="container">
  <app-profile-container></app-profile-container>
</main>

Then, go to src/app/app.component.scss, and include this:

.header {
  background: #ddd;
  border-bottom: 1px solid #ccc;
  margin: 0;
  padding: 1rem;
  box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2);
}

.container {
  display: flex;
  justify-content: center;
  margin-top: 2rem;
}

Now, the only thing we cannot forget to do is add ProfileComponent, and ProfileHostDirective, to the AppModule declarations array. Go to src/app/app.module.ts:

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { ProfileHostDirective } from './profile/profile-host.directive';
import { ProfileComponent } from './profile/profile.component';

@NgModule({
  declarations: [AppComponent, ProfileHostDirective, ProfileComponent],
  imports: [BrowserModule, AppRoutingModule],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule {}

And we are done.

Conclusion

I hope that you had as much fun coding this as I did while writing this code. Now you know how to dynamically load components with lazy loading. With this knowledge, you can reduce the main bundle size, and make the experience better for your users. If you are having any problems, feel free to reach out to me via Twitter.

This Dot is a consultancy dedicated to guiding companies through their modernization and digital transformation journeys. Specializing in replatforming, modernizing, and launching new initiatives, we stand out by taking true ownership of your engineering projects.

We love helping teams with projects that have missed their deadlines or helping keep your strategic digital initiatives on course. Check out our case studies and our clients that trust us with their engineering.

SSR Finally a First-Class Citizen in Angular?

I am sure you've already heard about server-side rendering (SSR). Generally, it's a technique used to deliver the HTML content generated by the server to the client. The client-side JavaScript framework then hydrates that HTML content to provide a fully interactive application. SSR provides numerous benefits if used correctly, including improved initial load times, better content indexing by search engines, and improved performance on lower-tier devices. Driven by the need for faster, more efficient web applications, with the rise in popularity of Node.js and, thus, server-side JavaScript, SSR has become a de facto standard in modern web development frameworks. At first, SSR was being provided as a part of meta-frameworks like Next.js, Nuxt, or Analog.js. Then, React introduced React Server Components, which marked a significant milestone in the way we think about front-end development. We think of front-end frameworks as being effectively full-stack, and a purely SPA approach is falling out of favor. However, I'm willing to bet that if you're a developer focused mostly on Angular, you may not have heard as much about SSR as your React counterparts. For a long time, Angular has been mostly focused on the SPA approach, and while we had Angular Universal or Analog.js, it was not as widely adopted. And that makes sense, given that Angular was widely regarded as best suited for complex, interactive applications, such as SaaS products or internal company tools, where SEO and initial load times were not as critical as they are for consumer-facing applications. Nevertheless, we have been blessed with the so-called Angular Renaissance, which has, among other things, brought SSR to the forefront of Angular development with the @angular/ssr package. Let's look at what Angular SSR is, how it works, and how you can get started. @angular/ssr The @angular/ssr package is not new; it was written from scratch. It's still Angular Universal. However, it's been pulled into the Angular CLI repository, and the appropriate schematics have been added to make it easier to use. What that means is that you can now add SSR to your Angular application with a single command: ` and you can generate a new SSR application with: ` And to make SSR a first-class citizen, the Angular team is planning to make it the default in the next version. But surely, it's not only rebranding and some CLI commands, you may say. And you're right. You may remember that hydration in Angular Universal has not been optimal as it was destructive and required essentially a complete re-render of the application, thus pretty much negating the benefits of SSR. With the introduction of non-destructive hydration in Angular 16 and its stability in Angular 17, the Angular team has taken a significant step forward in making SSR a first-class citizen. How to Make an SSR-capable Angular Application Let's look at how to use Angular SSR in practice by creating a simple SSR app. First, we need to create a new Angular application with SSR support: ` That will generate a few server-specific files: - server.ts, which is an Express server configured to handle Angular SSR requests by default but can also be extended to handle API routes, or anything else that Express can handle. - src/app/app.config.server.ts provides configuration for the server application similar to your app.config.ts, which defines the configuration for your client application. Both export an instance of ApplicationConfig - src/main.server.ts bootstraps the server application in a similar way to what main.ts does for your client app by calling the bootstrapApplication function. You should have an SSR application ready just like that. You can verify that by running ng serve. The terminal output should show you information about the server bundles generated, and you should be able to see the default app when going to http://localhost:4200. Open the Developer Tools and check the console to see that hydration is enabled. You'll see a message with hydration-related stats, such as the number of components and nodes hydrated. Speaking of hydration... Client Hydration If you open the src/app/app.config.ts in your new SSR application, you'll notice one interesting provider: provideClientHydration(). This provider is crucial for enabling hydration - a process that restores the server-side rendered application on the client. Hydration improves application performance by avoiding extra work to re-create DOM nodes. Angular tries to match existing DOM elements to the application's structure at runtime and reuses DOM nodes when possible. This results in a performance improvement measured using Core Web Vitals statistics, such as reducing the Interaction To Next Paint (INP), Largest Contentful Paint (LCP), and Cumulative Layout Shift (CLS). Improving these metrics also positively impacts SEO performance. Without hydration enabled, server-side rendered Angular applications will destroy and re-render the application's DOM, which may result in visible UI flicker, negatively impact Core Web Vitals like LCP, and cause layout shifts. Enabling hydration allows the existing DOM to be reused and prevents flickering. Event Replay and Improved Debugging With Angular 18, event replay, a feature that significantly enhances the SSR experience, came into developer preview. Event replay captures user interactions during the SSR phase and replays them once the application is hydrated. This ensures that user actions, such as adding items to a cart, are not lost during the hydration process, providing a seamless user experience even on slow networks. To enable event replay, you can add withEventReplay to your provideClientHydration call: ` Furthermore, Angular 18 takes another step towards making SSR a first-class citizen by enhancing the debugging experience with Angular DevTools. Now, DevTools include overlays and detailed error breakdowns, empowering developers to visualize and troubleshoot hydration issues directly in the browser. Constraints However, hydration imposes a few constraints on your application that are not present without hydration enabled. Your application must have the same generated DOM structure on both the server and the client. The hydration process expects the DOM tree to have the same structure in both environments, including whitespaces and comment nodes produced during server-side rendering. Direct DOM Manipulation The fact that server and client DOM structures must match means that components that manipulate the DOM using native DOM APIs or use innerHTML or outerHTML will encounter hydration errors. The errors are thrown because Angular is unaware of these changes and cannot resolve them during hydration. Examples include accessing the document, querying for specific elements, and injecting additional nodes using appendChild. Detaching DOM nodes and moving them to other locations will also cause errors. Direct DOM manipulation is generally considered bad practice in Angular, so I recommend refactoring your components to avoid it regardless of hydration. However, in warranted cases where refactoring is not feasible, you can use the ngSkipHydration attribute until a hydration-friendly solution can be implemented. You can use it directly in a template: ` or as a host binding: ` > Note: The ngSkipHydration attribute forces Angular to skip hydrating the entire component and its children. So use this attribute carefully, as, for example, applying it to your root application component would effectively disable hydration for the entire application. Valid HTML Structure Another constraint is that invalid HTML structures in component templates can result in DOM mismatch errors during hydration. Common issues include: - without a - inside a - inside an - inside another Again, if you have an invalid HTML, you should fix this regardless of hydration. If you are unsure about your HTML's validity, you can use the W3 validator to check it. Zoneless apps or custom Zone.js Hydration relies on a signal from Zone.js when it becomes stable. Custom or "noop" Zone.js implementations may thus disrupt the timing of this event, triggering the serialization or cleanup process too early or too late. This configuration is not yet fully supported. While Zoneless is already available in developer preview and we could assume this issue will be resolved when it lands as stable, there is no explicit ETA mentioned in the official roadmap. I18n One of the biggest blockers for adoption of client hydration was the lack of support for internationalization with hydration. By default, Angular 17 skipped hydration for components that used i18n blocks, re-rendering them from scratch. In Angular 18, however, hydration for i18n blocks got into developer preview. To enable hydration for i18n blocks, you can add withI18nSupport to your provideClientHydration call. ` Third-Party Libraries with DOM Manipulation The last thing to consider is third-party libraries that manipulate DOM, such as D3 charts. They could cause DOM mismatch errors when hydration is enabled. You can use the ngSkipHydration attribute to skip hydration for components rendered using these libraries. Conclusion The Angular team has been doing great work to make the framework more modern and competitive, hearing the community feedback and adjusting the roadmap accordingly. And SSR is an excellent example of that. With the introduction of non-destructive hydration in Angular 16 and making it stable in Angular 17, the Angular team has taken a significant step forward in making SSR a first-class citizen in Angular. The @angular/ssr package is now part of the Angular CLI, making adding SSR to your Angular application easier. The Angular team plans to make SSR the default in the next version, further solidifying its position in the Angular ecosystem. However, as with any new feature, there are some constraints and best practices to follow when using SSR with Angular. You should be aware of hydration's limitations and ensure your application is compatible with it. However, if you follow the guidelines provided by the Angular team, you should be able to take advantage of the benefits of SSR without any significant issues....

Jun 26, 2024

8 mins

AngularJavaScriptExpress.js

4 Angular Component Libraries That are Perfect for Beginners

For beginners starting with Angular, the journey can feel daunting, especially when it comes to setting up projects from scratch. However, there is a range of outstanding Angular component libraries that alleviate this initial hurdle: ready-made toolkits, empowering newcomers to start building Angular applications without the complexities of bootstrapping their projects. Let’s take a look! Angular Material Angular Material is a UI component library by Google for Angular applications. It provides a variety of pre-built components following the Material Design guidelines, offering customization options, responsive design, and accessibility features. It's seamlessly integrated with Angular and offers extensive documentation and community support. NG-ZORRO NG-ZORRO is an Angular UI component library based on Ant Design by Alibaba. It offers a variety of customizable components for building modern web applications. With seamless Angular integration, responsive design, and accessibility features, NG-ZORRO simplifies development while following Ant Design principles. NG Bootstrap NG Bootstrap is a library for Angular developers to easily incorporate Bootstrap components into their applications without relying on jQuery. It offers Angular-specific directives and components, ensuring compatibility and performance within Angular projects while maintaining Bootstrap's responsive design and customization options. Clarity Design System Clarity is an open-source design system by VMware that offers a set of Angular components for building enterprise-scale applications. It provides components specifically tailored for data-centric applications, dashboards, and complex user interfaces. Clarity Design System emphasizes clarity, consistency, and usability in its components. The beginner’s journey can be both exhilarating and challenging. However, with the advent of powerful component libraries like Angular Material, NG-ZORRO, NG Bootstrap, and the Clarity Design System, the path becomes significantly smoother. These libraries offer pre-built components and design systems that eliminate the need to bootstrap projects from scratch. As beginners embark on their Angular journey, these libraries provide a sturdy foundation, allowing them to dive into development with confidence. By harnessing the capabilities of these libraries, beginners can not only expedite their learning curve but also craft exceptional Angular applications with ease and efficiency....

Mar 14, 2024

2 mins

Angular

Building a Stripe App: A Step-by-Step Guide to QR Code Generation

Building a Stripe App: A Step-by-Step Guide to QR Code Generation Why Build a Stripe App? I recently participated in an audio space with the Stripe team, and something they said really stuck with me: the Stripe app store is a growing area that isn't overly saturated yet. There's a lot of potential for new apps, and companies can use this opportunity to grow. I work at a company called This Dot Labs, and we've created several Stripe apps and even own one. After looking at the data, I can confirm that the Stripe team was right! Creating a QR Code Generator App For this tutorial, we'll build a QR code app that can take a URL and generate a code for it. This is a good use case to help you understand the ins and outs of Stripe's developer tools. Why QR Codes? QR codes are useful tools that have become common in e-commerce, restaurants, and other industries. While Stripe already has a QR code tool, we'll make our own to familiarize ourselves with their syntax and problem-solving approaches. Project Structure Before we dive into the implementation, let's look at the structure of our Stripe App QR Code project: * .vscode: Contains settings for Visual Studio Code * source/views: Holds the main application views * .gitignore: Specifies files to ignore in version control * stripe-app.json: Defines the Stripe app configuration * ui-extensions.d.ts: TypeScript declaration file for UI extensions * .build: this is where the built Stripe app gets placed. Step-by-Step Implementation 1\. Install Stripe Locally First, you need to install Stripe on your local machine. The documentation provides great instructions for this: * For Mac users: Use Brew to install * For Windows users: Download the package and add it to your environment variables You can find the details here in the stripe docs to install the Stripe CLI https://docs.stripe.com/stripe-cli When using Windows, you must do stripe login from Powershell, NOT from Git bash or any other tool. After the server is up, then you can continue using git bash for everything else. After stripe login, you need to enter stripe apps start. Once you do that, the server is up and running and you can go back to using git bash or any other tool. 2\. Install Dependencies We'll be using an extra package for QR code generation. Install it using npm: ` 3\. Set Up the Main Component Let's look at the home.tsx file, where we'll use Stripe's UI components: ` These components are similar to other UI libraries like Bootstrap or Tailwind CSS. 4\. Create the UI Structure Our app will have: * An input field for the URL * Validation using a regex pattern * Error handling for invalid URLs * QR code generation and display Here is the Home.tsx file that is located in the src/views folder ` * ContextView` is at the top level of the app where we see the Title and the link to the Stripe Docs that we placed in our Context View. * Box is how you use Divs. * Banners can be used to show notification errors or any other item you wish to display. * Textfields are input fields. * Everything else is pretty self-explanatory. 5\. Handle Content Security Policy One problem I personally ran into was when I tried to redirect users, the Stripe policies would block it since I did not express that I knew what it was doing. I had to go into the stripe-app.json file and mention the specific security policies. For this particular exercise, I kept these as null. This is my stripe-app.json file. ` 6\. Configure App Views As you can see here, the stripe-app.json file shows the views for each file I have. The Home.tsx file and the Invoice.tsx are also included This is our way of saying that for each view we have, show the app functionality on that page. Our stripe-app.json file will show it but also, the manifest.js file in our .build folder will also show the same. Any view that doesn't have a file will not show the application's functionality. So, if I were to go to transactions, the app would not show the same logic as the home or invoices page. By following these steps, you'll have a fully functional QR code generator app for Stripe. This is just a simple example, but the potential for Stripe apps is massive, especially for businesses serving e-commerce customers. If you need help or get stuck, don't hesitate to reach out, danny.thompson@thisdot.co. The Stripe team is also very active in answering questions, so leverage them as a resource. Happy coding!...

Dec 18, 2024

4 mins

stripe

Understanding the Difference Between `:focus` and `:focus-visible` in CSS

Understanding the Difference Between :focus and :focus-visible in CSS I have learned my fair share about the importance of keyboard accessibility, so I know that visual indication of the focused element is very important. But the well-known :focus pseudo-class is not always the best fit for this job. That's where :focus-visible comes in. Let's look at the differences between these two pseudo-classes and explore the best practices for using them effectively. What is the :focus Pseudo-Class? The :focus pseudo-class is a CSS selector that applies styles to any element that receives focus, regardless of how that focus was triggered. This includes focus events from keyboard navigation, mouse clicks, and touch interactions. Example Usage of :focus ` In this example, the button will display a blue outline whenever it is focused, whether the user clicks on it with a mouse, taps it on a touchscreen, or navigates to it using the keyboard. What is the :focus-visible Pseudo-Class? The :focus-visible pseudo-class is more specialized. It only applies styles to an element when the browser determines that the focus should be visible. This typically occurs when the user navigates via the keyboard or assistive technologies rather than through mouse or touch input. Example Usage of :focus-visible ` Here, the button will only show a blue outline when focused through keyboard navigation or another input method that usually requires visible focus indicators. Key Differences Between :focus and :focus-visible :focus - Behavior: Applies to any element that receives focus, regardless of the input method. - Use Cases: Ensures that all interactions with the element are visually indicated, whether by mouse, keyboard, or touch. :focus-visible - Behavior: Applies styles only when the focus should be visible, such as using a keyboard or assistive technology. - Use Cases: Ideal for scenarios where you want to provide focus indicators only to keyboard and assistive technology users while avoiding unnecessary outlines for mouse and touch users, typically required by design. Accessibility Implications :focus - Pros: - Guarantees that all users can see when an element is focused, which is critical for accessibility. - Cons: - Can lead to a suboptimal experience for mouse users, as focus styles may appear unnecessarily during mouse interactions. :focus-visible - Pros: - Enhances user experience by showing focus indicators only when necessary, thus keeping the interface clean for mouse and touch users. - Tailors the experience for keyboard and assistive technology users, providing them with clear visual cues. - Cons: - Additional considerations may be required to ensure that focus indicators are not accidentally omitted, especially in older browsers that do not support :focus-visible. - There may be cases where you want to show focus indicators for all users, regardless of input method. Best Practices for Using :focus and :focus-visible To achieve the best accessibility and user experience, combining both :focus and :focus-visible in your CSS is often a good idea. Combining :focus and :focus-visible ` Here is a Stackblitz example of what such styling could look like for you to try out and play with. Additional Tips - Test with Keyboard and Assistive Technology: Ensure that your web application is navigable using a keyboard (Tab, Shift + Tab, etc.) and that focus indicators are visible for those who rely on them. It's never a bad idea to include accessibility testing in your e2e testing suite. - Provide Clear Focus Indicators: Make sure that focus indicators are prominent and easy to see. A subtle or hard-to-spot focus indicator can severely impact accessibility for users who rely on keyboard navigation. Conclusion The :focus-visible pseudo-class offers a more refined way to manage focus indicators, improving accessibility and user experience, particularly for keyboard and assistive technology users. By understanding the differences between :focus and :focus-visible, and applying best practices in your CSS, you can create more accessible and user-friendly web applications. Remember, accessibility should never be an afterthought. By thoughtfully applying focus styles, you ensure that all users, regardless of how they interact with your site, can easily navigate and interact....

Nov 8, 2024

3 mins

AccessibilityCSSPlaywright

Let's innovate together!

We're ready to be your trusted technical partners in your digital innovation journey.

Whether it's modernization or custom software solutions, our team of experts can guide you through best practices and how to build scalable, performant software that lasts.

Loading Components Dynamically in Angular 9 with Ivy

Loading Components Dynamically in Angular 9 with Ivy

The Problem

Solution

Implementation

Conclusion

You might also like

SSR Finally a First-Class Citizen in Angular?

4 Angular Component Libraries That are Perfect for Beginners

Building a Stripe App: A Step-by-Step Guide to QR Code Generation

Understanding the Difference Between `:focus` and `:focus-visible` in CSS

Let's innovate together!

You might also like

SSR Finally a First-Class Citizen in Angular?

4 Angular Component Libraries That are Perfect for Beginners

Building a Stripe App: A Step-by-Step Guide to QR Code Generation

Understanding the Difference Between `:focus` and `:focus-visible` in CSS