TypeScript中如何限制Record/对象的键，禁止使用保留键？

你当前的实现仅能检测值的冲突，但键的约束未生效——原因在于Exclude<T, DimensionKeys>的写法无法正确限制传入对象的键：当泛型T包含DimensionKeys的成员时，Exclude<T, DimensionKeys>会被解析为never，而TypeScript允许非空对象赋值给Record<never, ...>类型，导致键的冲突无法被检测。

以下是两种可行的解决方案，均可同时限制传入对象的键和值不能与DIMENSIONS的键值重复：

方案一：条件类型约束 #

const DIMENSIONS = {
  userType: 1,
  moduleVersion: 2
} as const;

type DimensionKeys = keyof typeof DIMENSIONS;
type DimensionValues = typeof DIMENSIONS[DimensionKeys];

function process<YourDim extends Record<string, number>>(
  yourDimensions: YourDim extends Record<infer K, infer V> 
    ? (K extends DimensionKeys ? never : V extends DimensionValues ? never : YourDim)
    : never
) {
  return {...yourDimensions, ...DIMENSIONS};
}

// 合法输入，正常执行
const myCorrectDimensions = { country: 33 } as const;
const combinedDimensions = process(myCorrectDimensions);

// 值冲突，触发类型错误
const myInvalidValueDimensions = { country: 1 } as const;
const badDimensions = process(myInvalidValueDimensions);

// 键冲突，触发类型错误
const myInvalidKeyDimensions = { userType: 79 } as const;
const badDimensions2 = process(myInvalidKeyDimensions);

该方案通过条件类型直接检查传入对象的键K和值V：只要K属于DimensionKeys，或V属于DimensionValues，就会返回never类型，强制TypeScript抛出错误。

方案二：直接泛型约束 #

const DIMENSIONS = {
  userType: 1,
  moduleVersion: 2
} as const;

type DimensionKeys = keyof typeof DIMENSIONS;
type DimensionValues = typeof DIMENSIONS[DimensionKeys];

function process<
  K extends Exclude<string, DimensionKeys>,
  V extends Exclude<number, DimensionValues>
>(yourDimensions: Record<K, V>) {
  return {...yourDimensions, ...DIMENSIONS};
}

// 合法输入，正常执行
const myCorrectDimensions = { country: 33 } as const;
const combinedDimensions = process(myCorrectDimensions);

// 值冲突，触发类型错误
const myInvalidValueDimensions = { country: 1 } as const;
const badDimensions = process(myInvalidValueDimensions);

// 键冲突，触发类型错误
const myInvalidKeyDimensions = { userType: 79 } as const;
const badDimensions2 = process(myInvalidKeyDimensions);

这种写法更简洁，直接通过泛型约束K为排除DimensionKeys的字符串类型，V为排除DimensionValues的数字类型，从根源上限制了传入对象的键值范围。

内容的提问来源于stack exchange，提问作者pseudogram