angular - angular2中的注解和装饰器有什么区别

Question

@Component({
  selector: 'app',
  template: 'Hello World!'
})
class MyComponent {}

what are the differences between annotations and decorators in angular2/4? how we can use the annotations and why? when we use decorators and why? what is tha image annotation Example: how i can do tag annotation for apicture in angular2/4 if any one have example please share it to me

提前谢谢你

Answer 1

装饰器是 Yehuda Katz 为 ECMAScript 2016 提议的标准，用于在设计时注释和修改类和属性。这听起来很像注解的作用对吗？好吧……有点。让我们看看装饰器长什么样:

// A simple decorator
@decoratorExpression
class MyClass { }

@Component 是一个注解，它告诉 Angular，注解所附加的类是一个组件。

@Component 是我们需要像这样从 Angular 框架导入的东西:

import { 
  ComponentMetadata as Component,
} from '@angular/core';

有关更多信息，您可以查看此 Difference .