Angular 4: What’s New and Why the Version Jump?

In March 2017, Angular 4 was officially released, surprising many in the development community not only with its new features but also with its unconventional version jump from Angular 2. The transition from Angular 2 to Angular 4 is not just about added functionality—it reflects a new approach to semantic versioning, performance improvements, and a vision for a more seamless Angular ecosystem.

For developers already using Angular 2, the good news is that Angular 4 remains backward-compatible. In this article, we’ll explore the key updates in Angular 4, the reasoning behind the version jump, and why now is the perfect time to upgrade your applications.

Why Skip Angular 3?

The Angular team’s decision to skip version 3 was primarily driven by versioning inconsistencies within Angular’s various libraries. Specifically, the Angular Router package had already reached version 3.x while other core packages were at version 2.x. To eliminate confusion and align all packages, the team decided to move directly to version 4.

This versioning leap also signals the Angular team’s adoption of semantic versioning (SemVer), ensuring that future releases clearly communicate breaking changes (major), new features (minor), or fixes (patches).

What’s New in Angular 4?

Angular 4 brings several enhancements aimed at improving developer productivity, application performance, and compatibility with modern standards. Let’s dive into the most notable updates.

1. Smaller and Faster Applications

One of the standout improvements in Angular 4 is its focus on reducing application size and improving runtime performance.

Template Compilation Enhancements: The Angular AOT (Ahead-of-Time) compiler has been optimized to generate less boilerplate code, resulting in smaller JavaScript bundles. Applications built with Angular 4 can see size reductions of up to 60% compared to Angular 2.
View Engine Improvements: The new View Engine preserves backward compatibility while reducing the size of generated code. This means faster load times and better overall performance.

2. Template Syntax Updates

Angular 4 introduces a new way to handle else statements in templates. Previously, developers relied on clunky workarounds to handle conditional rendering. With Angular 4, you can now use *ngIf with else to streamline your templates:

<div *ngIf="isLoggedIn; else loginPrompt">
  Welcome back, user!
</div>
<ng-template #loginPrompt>
  <p>Please log in to continue.</p>
</ng-template>

This improvement simplifies the syntax and makes templates more readable and maintainable.

3. Animation Package

In Angular 4, animations have been moved to their own package, @angular/animations. This separation helps reduce the size of the main Angular bundle for applications that don’t use animations.

To use animations, you’ll now import the new module:

import { BrowserAnimationsModule } from '@angular/platform-browser/animations';
@NgModule({
  imports: [BrowserAnimationsModule],
  ...
})
export class AppModule { }

4. Improved TypeScript Compatibility

Angular 4 supports TypeScript 2.1 and 2.2, bringing better type checking and features like async/await. This ensures that Angular developers can take full advantage of the latest improvements in the TypeScript ecosystem.

5. Structural Directives and Binding Improvements

Structural directives like *ngFor and *ngIf now offer improved syntax for working with local variables. For example, you can use let syntax directly in your templates for cleaner code:

<div *ngFor="let item of items; let i = index">
  {{ i }}: {{ item }}
</div>

Why Upgrade to Angular 4?

If you’re already using Angular 2, upgrading to Angular 4 is straightforward and comes with significant benefits. The backward compatibility ensures that existing code will work as expected, while the smaller bundle sizes and improved performance make it worthwhile for any production application.

For new projects, Angular 4 provides the foundation for building modern, scalable, and high-performance web applications. With its focus on developer productivity and adherence to best practices, Angular 4 solidifies Angular’s position as a leading front-end framework.

Roadmap for the Future

Angular 4 is part of a larger vision for Angular’s development lifecycle. The Angular team has committed to regular six-month release cycles, with Angular 5 planned for later in 2017. These frequent updates aim to introduce new features and improvements without breaking existing applications.

Additionally, the team’s focus on semantic versioning means that developers can trust the Angular ecosystem to evolve predictably, making it easier to plan upgrades and stay up to date.

Conclusion

Angular 4 is more than just a version number—it’s a milestone in the framework’s journey to becoming the best-in-class solution for building web applications. With its focus on performance, developer-friendly enhancements, and compatibility, Angular 4 sets the stage for even greater things to come.

Whether you’re maintaining an Angular 2 application or starting a new project, upgrading to Angular 4 is a decision you won’t regret. The tools and features it provides will save you time, improve your applications, and ensure that your projects are future-ready.

Categories:AngularJavascript