期望数组在固定大小的类型文本之间使用元组？

Question

我有一个函数，它接受一个形状为Record<string, number[]>的参数，其中数组可以是1到2个数字。

我很难将其限制为1或2，并尝试了以下几种方法：

const obj = { 'a': [0, 10], 'b': [11, 20], 'c': [21] };
function bar({data}: DataShape) {}

type DataShape = {
  data: Record<string, [number, number?]> 
}
const foo = bar({ data: obj }) 
// Type 'number[]' is not assignable to type '[number, (number | undefined)?]'.
// Target requires 1 element(s) but source may have fewer

// -------------------------------------------------------------
// Tried creating two defined tuple types
type DataShape = {
  data: Record<string, [number, number] | [number]> 
}
const foo = bar({ data: obj })
// Type 'number[]' is not assignable to type '[number, number]'.
// Target requires 2 element(s) but source may have fewer.

但是不能让number[]与[number]元组的交叉工作。有办法用number[]限制1...n吗？

Answer 1

对数组使用类型，并约束obj，如下所示：

type MyArray = [number, number?]

const obj: Record<string, MyArray> = { 'a': [0, 10], 'b': [11, 20], 'c': [21] };

function bar({data}: DataShape) {}

type DataShape = {
  data: Record<string, MyArray> 
}

const foo = bar({ data: obj })