如何在Typescript中使用动态键定义类型安全集合，并且仍具有智能感知支持

Question

我正在使用接口在Typescript中定义类型安全对象，并提供易于维护的代码结构。但是，在某些情况下，智能感知会被破坏。

当键未知并且仍要完成代码时，最好的方法是什么？

这是一个简单的例子，显示我的意思：

interface IObject {
  name: string,
  value: number
};

// here is the type safe collection interface
interface ICollection {
  [key: string]: IObject
};

// ...

// here is the type safe collection
let collection: ICollection = {
  a: {
    name: "a",
    value: 1
  },
  b: {
    name: "b",
    value: 2
  }
};

// here is the type unsafe collection
let collection2 = {
  a: {
    name: "a",
    value: 1
  },
  b: {
    name: "b",
    value: 2
  },
  c: {
    key: 1,
    status: true
  }
};

// ...

console.log(collection2.a.value); // this works ok, but it's not type safe
console.log(collection.a.value); // this is type safe, but there is no more intellisense support

Answer 1

我认为您正在寻找此处描述的答案：https://stackoverflow.com/a/49630741/11005213

遵循这些原则：

interface IObject {
  name: string;
  value: number;
};

interface IUnsafeObject extends Partial<IObject> {
  // if you know the type you can narrow it down here
  // e.g. [key: string]: boolean | number
  [key: string]: any;
}

interface ICollection<TType> {
  [key: string]: TType
};

let collection: ICollection<IObject> = {
  a: { name: "a", value: 1 },
  b: { name: "b", value: 2 }
};

let collection2 : ICollection<IUnsafeObject> = {
  a: { name: "a", value: 1 },
  b: { name: "b", value: 2 },
  c: { key: 1, status: true }
};

您还可以使用类型代替接口来实现相同的目的：

type MyObject = {
  name: string,
  value: number
};

type MyUnsafeObject = { [key: string]: any } & Partial<MyObject>;

另请参见：部分-https://www.typescriptlang.org/docs/handbook/utility-types.html#partialt泛型-https://www.typescriptlang.org/docs/handbook/generics.html