Angular基础简介

待我称王封你为后i 2022-05-25 02:35 239阅读 0赞

**What is Angular？**

Angular is a platform and framework for building client applications in HTML and TypeScript. Angular is itself written in TypeScript. It implements core and optional functionality as a set of TypeScript libraries that you import into your apps.

**Develop：**

Angular4 is not rebuilt from Angular JS. It is a completely new one . See the picture below.

![Image 1][]![Image 1][]![20180506210058318][]

**Angular's Architecture**

![Image 1][]![Image 1][]![20180506210127480][]

The basic building blocks of an Angular application are NgModules, which provide a compilation context for components. NgModules collect related code into functional sets; an Angular app is defined by a set of NgModules. An app always has at least a root module that enables bootstrapping, and typically has many more feature modules. Every Angular app has at least one NgModule class, the root module, which is conventionally named AppModule and resides in a file named app.module.ts. You launch your app by bootstrapping the root NgModule.

A component controls a patch of screen called a view. Components use services, which provide specific functionality not directly related to views. Service providers can be injected into components as dependencies, making your code modular, reusable, and efficient. Every Angular application has at least one component, the root component that connects a component hierarchy with the page DOM. Each component defines a class that contains application data and logic, and is associated with an HTML template that defines a view to be displayed in a target environment.

For data or logic that is not associated with a specific view, and that you want to share across components, you create a service class. A service class definition is immediately preceded by the @Injectable decorator. The decorator provides the metadata that allows your service to be injected into client components as a dependency.

Thanks for your reading . Next artical will be "Set up the development environment".

[Image 1]: 
[20180506210058318]: /images/20220525/30f41240eaa646a98d5534a4c4eb3ad4.png
[20180506210127480]: /images/20220525/73d661ded8384b2594bae2ca0820fc27.png