AngularJS是Angular 1, https://angular.io/guide/ajs-quick-reference 有更详细的信息；
MVVM（Model-View-ViewModel）组件相关；component based and allows rapid creation of UI features.
React can be used as a UI library to render elements
React Elements are the smallest building blocks of React apps. Components are larger building blocks that define independent and reusable pieces to be used throughout the application. JSX (JavaScript XML)
在react推出next之后,vue也推出了nuxt， nuxt是nodejs+vue.js有利于SEO,UI渲染不同于模板引擎渲染
The Vue.js core library focuses on the View layer only.
Components in Vue are small, self-contained, and can be reused throughout the application. Single File Components (SFCs) with the .vue extension contain HTML, CSS, and JavaScript so that all relevant code resides in one file.
Angular: 模块、组件和服务；如果僅僅用於PC 端的WEB開發， Angular 1.x足以應對； 如果是用於 mobile app ，在用戶體驗方面，略顯捉襟見肘；Angular 1 代碼是基於 JavaScript 寫的；在 Angular 1 中，最為常用的是 $scope 在 Angular 2和4中被去掉了。在新版本中，更多推崇的是 directive 和 controller, 通過對 component 組件的split（分割），從而實現代碼的復用，directive就是ng-开头的，controller就是三套架构里的其中之一；
Projects in Angular are structured into Modules, Components, and Services.Angular is built in TypeScript.
Aside from components, Angular supports modules and services.
Start coding new UI features with Angular
Template basics, bindings，filter or pipe "|", *ngFor, let
Template directives
https://angular.io/guide/ajs-quick-reference
ng-controller to @Component, ng-model, ng-repeat, ng-modules
controller function turn to component class
Modules/controllers/components
In AngularJS, you write the code that provides the model and the methods for the view in acontroller.In Angular, you build acomponent.
Inject dependencies
https://angular.io/guide/ajs-quick-reference
ready-to-use components
Angular is part of the well-known MEAN stack that combines Angular with MongoDB, ExpressJS, and NodeJS. Similar to the MERN() stack, it relies entirely on JavaScript for both the front-end and back-end.
Angular, React, and Vue can all be used to develop Progressive Web Apps, also known as PWAs.
