打字稿解构与所需参数 [英] Typescript destructuring with required parameter

问题描述

编辑抱歉，我的问题有点不清楚.我要强制始终需要getList参数.所以我没有默认值.例如，我希望用户始终提供一个获取列表

Edit Sorry my question was a bit unclear. I want to enforce that the getList Parameter is always required. So I don't have a default value for it. e.g I want the user always to supply a getlist

我正在尝试创建一个具有一些可选参数和一些必需参数的构造器

I'm trying to create a constuctor with some optional parameters and some required

export class PageConfig {
    constructor({
        isSliding = false,
    }: {
        isSliding?: boolean
        getList: (pagingInfo: PagingInfo) => Observable<any>
    } = {  }) { }
}

执行此操作时出现错误

类型"{}"中缺少getList，但类型...中必需.

getList is missing in type '{}' but required in type ...

我希望能够在像这样的类中使用它:

I would like to be able to use this in a class like so:

class UsersPage {

    config = new pageConfig({ this.getList })    

    getList(pagingInfo: PagingInfo) {
      // do work...
    }
}

注意::我已为该示例简化了类，但我拥有更多的属性，我想利用解构方法，因此无需配置其他类的实例化.比声明中的

Note: I've simplified the class for this example but I have a lot more properties, I'd like to leverage desturcturing so I don't have to configure the instantiation of my classes other than from the declaration

如何强制销毁过程中必须传递getList?

How can I enforce that getList must be passed during destructuring?

推荐答案

您对PageConfig构造函数参数使用默认值{}，但是在类型中按需标记了getList.如果我对您的理解正确，则希望始终设置构造函数参数和getList，因此将代码更改为:

You use a default value {} for the PageConfig constructor argument, but you marked getList as required in the type. If I understand you correctly, you want to have the constructor argument and getList always set, so change your code to:

export class PageConfig {
  constructor({
    getList,
    isSliding = false
  }: {
    getList: (pagingInfo: PagingInfo) => Observable<any>;
    isSliding?: boolean;
  }) {
    … // use getList and isSliding
  }
}

这种语法(使用默认值进行销毁)有时会有点麻烦.它变得更清晰，当你提取构造函数参数类型.

This syntax (destructuring with default values) can be a bit cumbersome sometimes. It gets clearer, when you extract the constructor argument type.

TypeScript文档示例

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