已开机，快来 Type-Challenges【 easy-11-tuple-to-object】

元组转对象

传入一个元组类型，将这个元组类型转换为对象类型。

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'}

要点

• T[number]所有元组类型组成的联合类型

解答

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

测试

type Expect<T extends true> = T;
type Equal<X, Y> = (<T>() => T extends X ? 1 : 2) extends (<T>() => T extends Y ? 1 : 2) ? true : false;
​
const tuple = ['tesla', 'model 3', 'model X', 'model Y'] as const
​
type cases = [
  Expect<Equal<TupleToObject<typeof tuple>, { tesla: 'tesla'; 'model 3': 'model 3'; 'model X': 'model X'; 'model Y': 'model Y'}>>,
]
​
// @ts-expect-error
type error = TupleToObject<[[1, 2], {}]>

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