使用 AMD 时如何在 d.ts 文件中引用 Typescript 枚举? [英] How to refer to Typescript enum in d.ts file, when using AMD?

问题描述

我想定义一个打字稿接口来表示，比如说，一个错误.像这样:

I want to define a typescript interface to represent, say, an error. Something like this:

enum MessageLevel {
    Unknown,
    Fatal,
    Critical,
    Error,
    Warning,
    Info,
    Debug
}

interface IMyMessage {
    name: string;
    level: MessageLevel;
    message: string;
}

就目前而言，这很好用.但是，现在(也许)我想在 .d.ts 文件中声明该接口，以便其他人可以使用它进行输入.但我不想在 .d.ts 文件中定义枚举，因为那将是实现而不是简单的输入信息.枚举应该在 .ts 文件中，我们称之为 messageLevel.ts:

This works fine as far as it goes. However, now (perhaps) I want to declare that interface in a .d.ts file so others can use it for typing. But I don't want to define the enum in the .d.ts file, since that would be implementation and not simple typing information. The enum should presumably be in a .ts file, let's call it messageLevel.ts:

///<amd-module name='MessageLevel'/>

export enum MessageLevel {
    Unknown,
    Fatal,
    Critical,
    Error,
    Warning,
    Info,
    Debug
}

而且我现在可以这样在我的 d.ts 输入文件中使用它:

and I can, at this point, use it in my d.ts typing file this way:

import * as ml from "./MessageLevel";

interface IMyMessage {
    name: string;
    level: ml.MessageLevel;
    message: string;
}

我可以完成这项工作，但我不喜欢将实现文件导入到类型文件中的级别混合.我也不喜欢在打字文件中实际实现枚举的想法.

and I can make this work, but I don't like the level-mixing of importing an implementation file into a typing file. Nor do I like the idea of actually implementing an enum in a typings file.

是否有一种干净的方法可以将实现和声明严格分开?

Is there a clean way to do this that keeps implementation and declaration strictly separate?

推荐答案

最佳解决方案可能取决于您是否更喜欢实际的 JavaScript 变量是数字、字符串还是其他.如果你不介意字符串，你可以这样做:

The best solution may depend on whether you have a preference for the actual JavaScript variable being a number, a string, or otherwise. If you don't mind String, you can do it like this:

///messagelevel.d.ts
export type MessageLevel = "Unknown" | "Fatal" | "Critical" | "Error";



///main.d.ts
import * as ml from "./MessageLevel";

interface IMyMessage {
    name: string;
    level: ml.MessageLevel;
    message: string;
}

因此，最终 JavaScript 将简单地表示为一个字符串，但只要您将它与不在该列表中的值进行比较，或者尝试将其分配给不同的字符串，TypeScript 就会标记错误.由于这是 JavaScript 本身最接近任何类型的枚举(例如，document.createElement("video") 而不是 document.createElement(ElementTypes.VIDEO)，这可能是表达这种逻辑的更好方式之一.

So in the end JavaScript, it will simply be represented as a string, but TypeScript will flag an error anytime you compare it to a value not in that list, or try to assign it to a different string. Since this is the closest that JavaScript itself has to any kind of enum (eg, document.createElement("video") rather than document.createElement(ElementTypes.VIDEO), it might be one of the better ways of expressing this logic.

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