判断一个string类型中是否有相同的字符
type CheckRepeatedChars<'abc'> // false
type CheckRepeatedChars<'aba'> // true
import type { Equal, Expect } from '@type-challenges/utils'
type cases = [
Expect<Equal<CheckRepeatedChars<'abc'>, false>>,
Expect<Equal<CheckRepeatedChars<'abb'>, true>>,
Expect<Equal<CheckRepeatedChars<'cbc'>, true>>,
Expect<Equal<CheckRepeatedChars<''>, false>>,
]