@angular/core

What is @angular/core?

The @angular/core package is a fundamental part of Angular, a popular front-end web application platform. It provides the critical runtime parts of the Angular framework, including the component decorator, directives, dependency injection, and the core Angular APIs necessary for building dynamic single-page web applications.

What are @angular/core's main functionalities?

Components

Components are the building blocks of Angular applications. They control a patch of screen called a view. The @Component decorator indicates that the class immediately below it is a component and provides metadata about the component.

"@Component({ selector: 'app-root', templateUrl: './app.component.html', styleUrls: ['./app.component.css'] }) export class AppComponent { title = 'My Angular App'; }"

Dependency Injection

Dependency Injection (DI) is a design pattern used in Angular to make components or classes dependent on interfaces rather than concrete implementations. This improves modularity and testability.

"constructor(private myService: MyService) {}"

Directives

Directives are classes that add additional behavior to elements in your Angular applications. With Angular's built-in directives, you can manage forms, lists, styles, and what users see.

"@Directive({ selector: '[appHighlight]' }) export class HighlightDirective { constructor(el: ElementRef) { el.nativeElement.style.backgroundColor = 'yellow'; } }"

Other packages similar to @angular/core

react

React is a popular JavaScript library for building user interfaces. It focuses on a component-based architecture similar to Angular but uses a different syntax and design philosophy. React emphasizes a one-way data flow and virtual DOM for efficient rendering.

vue

Vue.js is a progressive JavaScript framework used for building UIs and single-page applications. It is designed from the ground up to be incrementally adoptable. Vue also focuses on the ViewModel part of the MVVM pattern and employs a reactive and composable data model.

README

Angular

The sources for this package are in the main Angular repo. Please file issues and pull requests against that repo.

Usage information and reference details can be found in Angular documentation.

License: MIT

Changelog

19.0.0-next.1 (2024-08-22)

Breaking Changes

core

• The autoDetect feature of ComponentFixture will now attach the fixture to the ApplicationRef. As a result, errors during automatic change detection of the fixture be reported to the ErrorHandler. This change may cause custom error handlers to observe new failures that were previously unreported.

compiler-cli

| Commit | Type | Description | | -- | -- | -- | | 9e87593055 | feat | ensure template style elements are preprocessed as inline styles (#57429) |

core

| Commit | Type | Description | | -- | -- | -- | | b063468027 | feat | support TypeScript 5.6 (#57424) | | 3b0dca75d6 | fix | Allow zoneless scheduler to run inside fakeAsync (#56932) | | f03d274e87 | fix | ComponentFixture autoDetect feature works like production (#55228) | | d4449fce21 | fix | handle hydration of components that project content conditionally (#57383) |

migrations

| Commit | Type | Description | | -- | -- | -- | | 4ae66f25d0 | fix | account for members with doc strings and no modifiers (#57389) | | ac93839d69 | fix | avoid migrating route component in tests (#57317) | | 58a79b6e43 | fix | preserve type when using inject decorator (#57389) |

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