Angular2模型类中的方法格式 [英] Method format within Angular2 model class

问题描述

我有一个基本的模型类(不是组件):

I have a basic model class (not a component):

export class catModel { 
 constructor(public name: string) { }
 getName: string {
  return this.name.toUpperCase();
 }
}

现在，我将尝试在这样的组件中使用此模型:

Now I'll try and use this model in a component like this:

feline: catModel = {name: 'simba' };

...当我编译时，出现以下错误:

...when I compile I get the following error:

类型'{{name:string}'不可分配给类型'catModel'.类型'{名称:字符串}'中缺少属性'getName'

Type '{ name: string }' is not assignable to type 'catModel'. Property 'getName' is missing in type '{ name: string }'

一旦从catModel中删除getName函数，它就可以正常工作，为什么不让我添加一个方法呢?

As soon as remove the getName function from the catModel it works fine, why won't it let me add a method?

推荐答案

这是因为Typescript使用结构类型系统.如 TypeScript文档:类型兼容性

It's because Typescript uses a structural type system. As stated in the TypeScript docs: Type Compatibility

TypeScript的结构类型系统的基本规则是，如果y至少具有与x

相同成员"表示属性和方法.如果您考虑这种推理，那将是非常合理的.通过将某些内容键入CarModel，您可以保证使用它的任何人都可以像CarModel一样操作.如果您的对象字面量中没有getName，则它不能是CarModel，因为它不遵守合同.

"same members" means properties and methods. If you think about this reasoning, it makes perfect sense. By typing something as CarModel, you are making a guarantee to anyone using it that it will behave like a CarModel. If you don't have a getName in your object literal, then it can't be a CarModel, as it doesn't follow the contract.

阅读上面的第二个链接.这是一个很棒的参考文件.

Read the second link above. It's a great reference document.

_{可能不是您的帖子中主要关注的内容，但是显而易见的解决方案是仅构造类new CarModel('simba')的实例.}

_{Probably not what the main concern in your post is about, but the obvious solution is to just construct an instance of the class new CarModel('simba').}

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