Tuple to Object

约 284 字小于 1 分钟

2026-02-11

题目

将一个元组类型转换为对象类型，这个对象类型的键/值和元组中的元素对应。

例如：

const tuple = ['tesla', 'model 3', 'model X', 'model Y'] as const

type result = TupleToObject<typeof tuple> // expected { 'tesla': 'tesla', 'model 3': 'model 3', 'model X': 'model X', 'model Y': 'model Y'}

解题思路

T[number] 即可遍历 T 元组中的元素。

答案

type TupleToObject<T extends readonly (number|string|symbol)[]> = {
  [P in T[number]]: P
}

验证

const tuple
 = ['tesla', 'model 3', 'model X', 'model Y'] as const

const tupleNumber
 = [1, 2, 3, 4] as const

const sym1
 = Symbol
(1)
const sym2
 = Symbol
(2)
const tupleSymbol
 = [sym1
, sym2
] as const

const tupleMix
 = [1, '2', 3, '4', sym1
] as const


type cases
 = [
  Expect
<Equal
<TupleToObject
<typeof tuple
>, { 'tesla': 'tesla', 'model 3': 'model 3', 'model X': 'model X', 'model Y': 'model Y' }>>,
  Expect
<Equal
<TupleToObject
<typeof tupleNumber
>, { 1: 1, 2: 2, 3: 3, 4: 4 }>>,
  Expect
<Equal
<TupleToObject
<typeof tupleSymbol
>, { [sym1
]: typeof sym1
, [sym2
]: typeof sym2
 }>>,
  Expect
<Equal
<TupleToObject
<typeof tupleMix
>, { 1: 1, '2': '2', 3: 3, '4': '4', [sym1
]: typeof sym1
 }>>,
]

// @ts-expect-error
type error
 = TupleToObject
<[[1, 2], {}]>

参考

映射类型 Mapped Types
索引访问类型 Indexed Types