TypeScript中动态导入命名空间变量的类型安全访问策略

// my_file.ts
export interface CustomType {
    propertyOne: string;
    propertyTwo: number;
}

export const MyThing: CustomType = {
    propertyOne: "name",
    propertyTwo: 2
};

export const AnotherThing: CustomType = {
    propertyOne: "Another",
    propertyTwo: 3
};

// consumer.ts
import * as allthings from "dir/folder/my_file";

function doStuff() {
   let currentThing = allthings['MyThing']; // ✅ 正常工作
   let name = 'MyThing';
   let currentThing2 = allthings[name]; // ❌ 报错：'string' 类型不能用于索引 'typeof import("...")'
}

import * as allthings from "dir/folder/my_file";

function doStuffWithConst() {
   const name = 'MyThing'; // `name` 的类型被推断为字面量类型 'MyThing'
   let currentThing = allthings[name]; // ✅ 正常工作
   console.log(currentThing.propertyOne);
}

doStuffWithConst();

import * as allthings from "dir/folder/my_file";

function doStuffWithAsConst() {
   let name = 'MyThing' as const; // `name` 的类型被强制为字面量类型 'MyThing'
   let currentThing = allthings[name]; // ✅ 正常工作
   console.log(currentThing.propertyTwo);
}

doStuffWithAsConst();

// my_file.ts (同上)
export interface CustomType {
    propertyOne: string;
    propertyTwo: number;
}

export const MyThing: CustomType = {
    propertyOne: "name",
    propertyTwo: 2
};

export const AnotherThing: CustomType = {
    propertyOne: "Another",
    propertyTwo: 3
};

// consumer.ts
import * as allthings from "dir/folder/my_file";

// 定义一个类型，表示 allthings 对象的所有有效键
type AllThingKeys = keyof typeof allthings; // 类型为 'MyThing' | 'AnotherThing'

function getValueFromAllThings(key: AllThingKeys): CustomType {
    return allthings[key]; // ✅ 正常工作，因为 key 被限制为 AllThingKeys 类型
}

function processDynamicKey(dynamicKey: string) {
    // 假设 dynamicKey 是从外部输入获取的
    if (dynamicKey === 'MyThing' || dynamicKey === 'AnotherThing') {
        // 在这里，我们可以安全地将 dynamicKey 断言为 AllThingKeys
        // 或者，更好的做法是先检查，再调用类型安全的函数
        const value = getValueFromAllThings(dynamicKey);
        console.log(`获取到 ${dynamicKey}:`, value.propertyOne);
    } else {
        console.warn(`键 '${dynamicKey}' 无效.`);
    }
}

processDynamicKey('MyThing'); // 输出: 获取到 MyThing: name
processDynamicKey('NonExistent'); // 输出: 警告: 键 'NonExistent' 无效.

interface CustomType {
  propertyOne: string;
  propertyTwo: number;
}

const allthings = {
  MyThing: {
    propertyOne: "name",
    propertyTwo: 2
  },
  AnotherThing: {
    propertyOne: "Another",
    propertyTwo: 3
  },
  // 如果这里添加一个不符合 CustomType 的项，TypeScript 会报错
  // InvalidThing: {
  //   someOtherProp: true // 报错：与 CustomType 不兼容
  // }
} satisfies Record<string, CustomType>; // 确保 allthings 的所有属性值都是 CustomType

// 此时，allthings 的类型仍然是推断出来的字面量类型：
// { MyThing: { propertyOne: string; propertyTwo: number; }; AnotherThing: { propertyOne: string; propertyTwo: number; }; }
// 但 TypeScript 已经检查了它是否满足 Record<string, CustomType>

type AllThingKeys = keyof typeof allthings; // 类型为 'MyThing' | 'AnotherThing'

function getValueFromAllThingsSatisfies(key: AllThingKeys): CustomType {
    return allthings[key]; // ✅ 正常工作
}

const item = getValueFromAllThingsSatisfies('MyThing');
console.log(item.propertyOne);