Typescript 如何正确地将元组表格输入到对象数组实用函数(如ZIP)中，避免在TypeScrip 5.2.2中合并所有值

我认为你遇到的主要问题是

{ [I in keyof TcolTuple as TcolTuple[I]]: TvalTuple[I] }

使用key remapping可以防止映射的类型为homomorphic(请参见What does "homomorphic mapped type" mean?)，因此不是像"0" | "1" | "2"那样映射mapping over just the numeric-like indices of the tuple，而是映射all个以上的索引，包括number，所有元素的混合.这就给了你你不满意的union.

这里最简单的改变是只显式地映射类似数字的索引，通过intersecting keyof TcolTuple与pattern template literal type `${number}`(如microsoft/TypeScript#40598中所实现的).它删除任何不是数字的字符串版本的内容. 例如，"0" | "1" | "2" | number | "length" | "find"与`${number}`相乘，得到的结果是"0" | "1" | "2".

这或多或少解决了这个问题:

declare function rowsToObjects<
  Tobj extends { [I in `${number}` & keyof TcolTuple as TcolTuple[I]]: TvalTuple[I] },
  TcolTuple extends readonly string[],
  TvalTuple extends { [J in keyof TcolTuple]: unknown }
>(cols: TcolTuple, ...rows: TvalTuple[]): Tobj[];

const objects = rowsToObjects(
  ['id', 'color', 'shape', 'size', 'to'] as const,
  [1n, 'red', 'circle', 'big', '0x0'] as const,
  [2n, 'green', 'square', 'small', '0x0'] as const,
  [3n, 'blue', 'triangle', 'small', '0x0'] as const,
)
/* const objects: {
    id: 1n | 2n | 3n;
    color: "red" | "green" | "blue";
    shape: "circle" | "square" | "triangle";
    size: "big" | "small";
    to: "0x0";
}[] */

就我个人而言，如果我为自己写这篇文章，我会:

• 使用const type parameters而不是要求呼叫者使用const assertions；
• 维护输入的元组类型，以便如果输入数组是强有序的，那么输出也是强有序的(例如，rowsToObjects(["a"],[0],[1])应该返回[{a: 0}, {a: 1}]，而不是{a: 0 | 1}[]；
• go 掉多余的generic个类型参数，只计算内联输出，而不是依赖default type arguments；
• 映射的类型参数使用大写字母，如I和J，而不是i和j，遵循命名约定以区分类型和变量(在{[P in K]: F<P>}中，P是类型参数，而不是变量名，因此p可能会混淆).

所有这些都不是至关重要的，但它给了我们

declare function rowsToObjects<
  const K extends readonly PropertyKey[],
  const V extends readonly Record<keyof K, unknown>[]
>(
  cols: K, ...rows: V
): { [I in keyof V]:
    { [J in `${number}` & keyof K as K[J]]:
      V[I][J]
    }
  };

const objects = rowsToObjects(
  ['id', 'color', 'shape', 'size', 'to'],
  [1n, 'red', 'circle', 'big', '0x0'],
  [2n, 'green', 'square', 'small', '0x0'],
  [3n, 'blue', 'triangle', 'small', '0x0'],
)
/* const objects: readonly [{
    id: 1n;
    color: "red";
    shape: "circle";
    size: "big";
    to: "0x0";
}, {
    id: 2n;
    color: "green";
    shape: "square";
    size: "small";
    to: "0x0";
}, {
    id: 3n;
    color: "blue";
    shape: "triangle";
    size: "small";
    to: "0x0";
}] */

Playground link to code