typescript Angular 2 模型：接口与类
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Angular 2 models: interface vs classes
提问by Tomas Eglinskas
I have a login/registration module and I want to write a model for them.
我有一个登录/注册模块，我想为它们编写一个模型。
I would use interfaces, but I need to have one predefined value.
我会使用接口，但我需要有一个预定义的值。
And I was wondering - should I put the predefined out as a constant (it won't be changed, altered) and use interfaces. Or write it as classes (as currently)
我想知道 - 我是否应该将预定义的内容作为常量（它不会被更改、更改）并使用接口。或将其写为类（如当前）
Currently, I wrote two separate classes - registration.model.ts, login.model.ts, could I be able to abstract to use only one model? (example: user.model.ts)
目前，我写了两个独立的类——registration.model.ts、login.model.ts，我可以抽象为只使用一个模型吗？（例如：user.model.ts）
Some examples:
一些例子：
export class LoginUser {
constructor(
private email,
private password,
// I need to have it, backend expects it to be sent
private connection = 'Username-Password-Authentication'
) { }
}
export class RegistrateUser {
constructor(
public name: string,
public lastName: string,
public email: string,
public password: string,
// I need to have it, backend expects it to be sent
private connection = 'Username-Password-Authentication'
) { }
}
采纳答案by Aluan Haddad
I would definitely use interfaces. It is a simple approach and follows the TypeScript recommendations for working with JSON.
我肯定会使用接口。这是一种简单的方法，并遵循使用 JSON 的 TypeScript 建议。
The property in question,
有问题的财产，
private connection = 'Username-Password-Authentication';
can well be added by the service that performs the request.
可以很好地由执行请求的服务添加。
This will also reduce code duplication because you can use a generic function or service to create this request object.
这也将减少代码重复，因为您可以使用通用函数或服务来创建此请求对象。
For example:
例如：
export default function withRequiredAuthProps<T>(model: T) {
return {...model, connection: 'Username-Password-Authentication'};
}
Then your Http service that sends the model back to the service can use a type constraint to verify that the property has been added before making the request
然后将模型发送回服务的 Http 服务可以使用类型约束来验证在发出请求之前是否已添加该属性
For example:
例如：
export default class MyHttpClient {
post<T extends {connection: 'Username-Password-Authentication'}>(url: string, body: T) {
//...
}
}
These are just meant as examples but they are based on code that is minimal, and that works.
这些只是作为示例，但它们基于最少且有效的代码。
回答by jarodsmk
just came across your question & was investigating the same thing.
刚刚遇到您的问题并正在调查同样的事情。
With reference to the Angular 2 Style docs here, the 'guideline' is to NOT implement an interface on the premise that a class alone can:
参考此处的Angular 2 Style 文档，“准则”是不实现接口的前提是单独的类可以：
- Act as an interface (if you use the implements keyword instead of the extends keyword)
- Be smaller than a class-implementing-interface
- 充当接口（如果您使用 implements 关键字而不是 extends 关键字）
- 比类实现接口小
As a rule of thumb:
根据经验：
Angular Guidelines> Typescript Guidelines(in the case of Angular 2 projects).
Angular 指南> Typescript 指南（在 Angular 2 项目的情况下）。
Hope this helps you out! :)
希望这可以帮助你！:)
