Angular entry component and declarative component case comparison
This time I will bring you a comparison of Angular entry components and declarative component cases. What are the precautions when using Angular entry components and declarative component cases. The following is a practical case, let's take a look.
Preface
Components are a very important part of Angular. The following article will introduce you to the Angular entry component. ) and the difference between declarative components. The difference between Angular's declarative components and entry components is reflected in the different loading methods of the two.
Declarative components are loaded through the selector declared by the component
The entry component (entry component) is loaded through the component Type dynamic loading
Declarative component
Declarative components will load the component through the selector declared by the component in the template.
Example
@Component({ selector: 'a-cmp', template: ` <p>这是A组件</p> ` }) export class AComponent {}
@Component({ selector: 'b-cmp', template: ` <p>在B组件里内嵌A组件:</p> <a-cmp></a-cmp> ` }) export class BComponent {}
In the BComponent template, use the selector<a-cmp></a-cmp>
statement to load AComponent.
Entry component (entry component)
The entry component loads the component through the specified component class.
is mainly divided into three categories:
Declared in
@Ng<a href="http://www.php.cn/code/8212.html" target="_blank">Module</a>.<a href="http://www.php.cn/wiki/1505.html" target="_blank">bootstrap</a>
Startup component, such as AppComponent.Others are loaded using component types through programming Dynamic component
Startup component
app.component.ts
@Component({ selector: 'app-root', templateUrl: './app.component.html', styleUrls: ['./app.component.scss'] }) export class AppComponent{}
app.module.ts
@NgModule({ declarations: [ AppComponent ], imports: [ BrowserModule, BrowserAnimationsModule, AppRoutingModule ], providers: [], bootstrap: [AppComponent] }) export class AppModule { }
in bootstrap The declared AppComponent is the startup component. Although we will use the component's selector<app-root></app-root>
position in index.html, Angular does not load the AppComponent based on this selector. This is where it can easily be misunderstood. Because index.html does not belong to any component template, Angular needs to load the component programmatically using the AppComponent type declared in bootstrap instead of using a selector.
Since Angular dynamically loads AppComponent, all AppComponent is an entry component.
Components referenced by routing configuration
@Component({ selector: 'app-nav', template: ` <nav> <a>首页</a> <a>用户</a> </nav> <router-outlet></router-outlet> ` }) export class NavComponent {}
We need to configure a route
const routes: Routes = [ { path: "home", component: HomeComponent }, { path: "user", component: UserComponent } ]; @NgModule({ imports: [RouterModule.forRoot(routes)], exports: [RouterModule] }) export class AppRoutingModule { }
Angular loads the component class specified by the route according to the configured route component instead of loading through the component's selector.
Configuring entry components
In Angular, the library components need to be configured in @NgModule.entryComponents
.
Since the components referenced in the startup component and routing configuration are both entry components, Angular will automatically add these two components to @NgModule.entryComponents
during compilation. For dynamic components written by ourselves, we need to manually add them to @NgModule.entryComponents
.
@NgModule({ declarations: [ AppComponent ], imports: [ BrowserModule, BrowserAnimationsModule, AppRoutingModule ], providers: [], entryComponents:[DialogComponent], declarations:[] bootstrap: [AppComponent] }) export class AppModule { }
I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!
Recommended reading:
How to deal with the conflict between double-click and click events in JS
How to write a custom script with vue Define components
The above is the detailed content of Angular entry component and declarative component case comparison. For more information, please follow other related articles on the PHP Chinese website!

JavaScript originated in 1995 and was created by Brandon Ike, and realized the language into C. 1.C language provides high performance and system-level programming capabilities for JavaScript. 2. JavaScript's memory management and performance optimization rely on C language. 3. The cross-platform feature of C language helps JavaScript run efficiently on different operating systems.

JavaScript runs in browsers and Node.js environments and relies on the JavaScript engine to parse and execute code. 1) Generate abstract syntax tree (AST) in the parsing stage; 2) convert AST into bytecode or machine code in the compilation stage; 3) execute the compiled code in the execution stage.

The future trends of Python and JavaScript include: 1. Python will consolidate its position in the fields of scientific computing and AI, 2. JavaScript will promote the development of web technology, 3. Cross-platform development will become a hot topic, and 4. Performance optimization will be the focus. Both will continue to expand application scenarios in their respective fields and make more breakthroughs in performance.

Both Python and JavaScript's choices in development environments are important. 1) Python's development environment includes PyCharm, JupyterNotebook and Anaconda, which are suitable for data science and rapid prototyping. 2) The development environment of JavaScript includes Node.js, VSCode and Webpack, which are suitable for front-end and back-end development. Choosing the right tools according to project needs can improve development efficiency and project success rate.

Yes, the engine core of JavaScript is written in C. 1) The C language provides efficient performance and underlying control, which is suitable for the development of JavaScript engine. 2) Taking the V8 engine as an example, its core is written in C, combining the efficiency and object-oriented characteristics of C. 3) The working principle of the JavaScript engine includes parsing, compiling and execution, and the C language plays a key role in these processes.

JavaScript is at the heart of modern websites because it enhances the interactivity and dynamicity of web pages. 1) It allows to change content without refreshing the page, 2) manipulate web pages through DOMAPI, 3) support complex interactive effects such as animation and drag-and-drop, 4) optimize performance and best practices to improve user experience.

C and JavaScript achieve interoperability through WebAssembly. 1) C code is compiled into WebAssembly module and introduced into JavaScript environment to enhance computing power. 2) In game development, C handles physics engines and graphics rendering, and JavaScript is responsible for game logic and user interface.

JavaScript is widely used in websites, mobile applications, desktop applications and server-side programming. 1) In website development, JavaScript operates DOM together with HTML and CSS to achieve dynamic effects and supports frameworks such as jQuery and React. 2) Through ReactNative and Ionic, JavaScript is used to develop cross-platform mobile applications. 3) The Electron framework enables JavaScript to build desktop applications. 4) Node.js allows JavaScript to run on the server side and supports high concurrent requests.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Atom editor mac version download
The most popular open source editor

Notepad++7.3.1
Easy-to-use and free code editor

Dreamweaver Mac version
Visual web development tools

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

SecLists
SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.
