Introduction

Hey there, Web Warriors!

Step right into Angular v17 – the ultimate web wizardry that's shaking up the digital realm! 🚀✨ Say goodbye to the old, clunky web and wave hello to sleek, lightning-fast websites that groove on any device!

Picture this: crafting sites smoother than jazz, loading faster than a shooting star, and performing better than a top-tier orchestra. Angular v17 isn't just an update; it's a whole new groove!

What's the buzz? We're talkin' about a brand-new approach that dances effortlessly between clients and servers, giving you the power to create apps that sing and swing in perfect harmony.

Get ready for turbocharged speeds, navigation smoother than a slick slide, and tools so user-friendly, they practically do the tango for you! This ain't your grandma's web development – it's a futuristic fiesta!

Join us on this wild ride as we unravel these mind-bending innovations, unlocking the door to a world where crafting modern, flexible, and downright snazzy web apps is a piece of cake. 🍰💃

Don't miss the party – let's jazz up web development together! 🎉✨

What's new ?

Server-Side Rendering (SSR)
Declarative control flow
Deferrable views
Signals
Angular Dev tools
Removal of @NgModule
Lazy Loading in v17

Server-Side Rendering (SSR)

Server-side rendering (SSR) is a technique for generating HTML content on the server instead of in the browser. This can improve the performance and SEO of Angular application.

With SSR, the initial HTML content is sent to the browser, which then hydrates the application and makes it interactive. This means that the user can start interacting with the application as soon as the initial HTML content is loaded, even before the rest of the application has been downloaded.

Benefits of SSR:

Improved performance: SSR can improve the perceived performance of the application by delivering the initial HTML content to the browser much faster than if the client had to download and render it all on its own.
Better SEO: Search engines can crawl and index the initial HTML content, which can improve the ranking of application in search results.
Reduced load on the client: By rendering the initial HTML content on the server, you can reduce the load on the client and make the application more responsive, especially on low-powered devices.

Enabling SSR

To create a new project with SSR, use the following command.

ng new <app-name> --ssr

To add it to an existing project, use the following command.

ng add @angular/ssr

Hydration

Hydration is the process of making an SSR-rendered application interactive. In Angular v17, hydration is more efficient than ever before. The Angular team has made several improvements to the hydration process, including:

Lazy loading: Angular now lazy loads modules during hydration, which can significantly improve performance.
Improved event handling: Angular now handles events more efficiently during hydration, which can make your application more responsive.
Reduced error handling: Angular now handles errors more efficiently during hydration, which can make your application more stable.

Declarative Control flow

Angular 17 introduces a stronger and better way to write code that controls how elements show up or disappear on a webpage. This new method replaces the old way of using Structural Directives like ngIf, ngFor, and ngSwitch. It's designed to be more effective and powerful for managing how things are displayed or hidden in an Angular application.

@if, @else if, @else blocks:

These blocks allow for conditional rendering of template content based on expressions.

<div>
  @if (a > b) {
    <p>{{a}} is greater than {{b}} </p>
  } @else if (b > a) {
    <p>{{a}} is less than {{b}} </p>
  }@else {
    <p>{{a}} is equal to {{b}} </p>
  }
</div>

@for, @empty blocks:

@for block provides a concise and expressive way to iterate over collections and render template content for each item.

@empty block handles scenarios where the collection being iterated over is empty.

<ul>
@for (item of items; track item.name) {
  <li> {{ item.name }} </li>
} @empty {
  <li> There are no items. </li>
}
</ul>

@switch, @case, and @default blocks:

These blocks enable switch-case logic for template rendering.

<div>
  @switch (product.category) {
    @case "electronics":
      <p>This product is an electronic device.</p>
    @case "apparel":
      <p>This product is a piece of clothing.</p>
    @default:
      <p>This product belongs to an unknown category.</p>
  }
</div>

Deferrable views

Deferrable views, also known as @defer blocks, are a powerful feature introduced in Angular v17 that allows you to selectively load specific components, directives, pipes, and their associated CSS based on user interaction or specific conditions. This feature is particularly useful for performance optimization, especially when dealing with large or resource-intensive components that may not be immediately needed or visible to the user.

key Benefits of Deferrable views:

Improved Initial Load Performance:

By deferring the loading of non-critical components, you can significantly reduce the initial bundle size of the application, resulting in faster initial loading and improved perceived performance.
Enhanced User Experience:

Deferrable views allow you to adapt the application's loading behavior based on user actions, ensuring that resources are allocated efficiently and only when necessary. This leads to a smoother and more responsive user experience.

Optimized Memory Usage:

By deferring the loading of unnecessary components, you can reduce the overall memory usage of the application, particularly on devices with limited memory resources.

Basic structure of a defer block

A defer block is defined using the @defer decorator and typically includes the following elements:

Trigger:

Specifies the condition that must be met before the deferred content is loaded. Triggers can be based on user actions, scroll position, or custom logic.

There are two options for configuring when this swap is triggered: on and when.

on specifies a trigger condition using a trigger from the list of available triggers below.

on idle
on viewport
on interaction
on hover
on immediate
on timer

Note: Multiple on triggers are always OR conditions. Similarly, on mixed with when conditions are also OR conditions.

when specifies an imperative condition as an expression that returns a Boolean.

Note: if when condition switches back to false, the defer block is not reverted back to the placeholder. The swap is a one-time operation. If the content within the block should be conditionally rendered, and if condition can be used within the block itself.

Loading Block (Optional):

Defines the HTML content to display while the deferred content is being loaded. This provides a visual indication that the content is loading and helps maintain a consistent user experience.

This includes @placeholder and @loading (It can optionally take parameters like minimum, after).

Error Block (Optional):

Defines the HTML content to display if an error occurs during the loading of the deferred content. This allows you to handle errors gracefully and provide appropriate feedback to the user.

This includes @error

Example of Deferring a Component Based on Scroll Position:

Consider a scenario where you have a long article with a comments section at the bottom. You can use a defer block to defer the loading of the comments section until the user scrolls down to the bottom of the article. This ensures that the comments section is only loaded when it is likely to be needed, improving initial load performance, and reducing memory usage.

<div class="article">
      ... Article content ...

    @defer (on viewport(commentSection)) {
        <comments-section />
    } @loading {
        <app-loading />
    } @error {
        <div class="error-message">Failed to load comments.</div>
    }
    <div #commentSection></div>
</div>

Signals

Signals were released as a developer preview with Angular 16. With Angular 17, Signal is stable and can be used.

You can refer here to know more about signals: Angular Signals

Angular Dev Tools

Angular Devtools now includes a nifty addition: the capability to visualize the injection tree. This feature proves highly beneficial for debugging the application in scenarios involving circular dependencies or instances where a token fails to resolve accurately.

Removal of @NgModule

Angular v17 introduced a significant shift in the framework's architecture, enabling the use of standalone components without the need for @NgModule. This change aims to streamline the development process by reducing boilerplate code and making it easier to create reusable components.

Benefits of Removing @NgModule

Reduced Boilerplate Code: Eliminates the need for @NgModule declarations and configurations, simplifying component creation and usage.
Improved Component Reusability: Makes it easier to create and reuse components across different parts of the application.
Simplified Dependency Management: Automatically resolves dependencies for standalone components without the need for manual configuration.
Enhanced Developer Experience: Reduces the cognitive load for developers, allowing them to focus on component behavior rather than module organization.

How to perform Lazy Loading:

Yeah, I heard you. By removal of @NgModule. How do we lazy load our components?
To understand this, you must need to explore my GitHub repository.

GitHub link: lazy-loading-in-angular-v17

Stackblitz link: Stackblitz-Lazy-Loading

Conclusion

Angular v17 ushers in a new era of web development, embracing groundbreaking features like SSR, declarative control flow, deferrable views, and more. With stability in Signals and advanced Dev Tools, this version simplifies complexities. The removal of @NgModule streamlines component creation and reuse. Lazy loading, now achievable without @NgModule, marks a paradigm shift in efficiency. Angular v17 shapes a future where crafting top-tier web apps is accessible and enjoyable. This update isn't just about code; it's an invitation to an innovative realm where speed, flexibility, and user-centric design harmonize. Embrace Angular v17—a pivotal step toward crafting captivating web experiences effortlessly. 🌐✨

Thanks for reading.

Angular Version-17

New features of Angular-v17