Length of String 2

约 249 字小于 1 分钟

2026-02-11

题目

Implement a type LengthOfString<S> that calculates the length of the template string (as in 298 - Length of String):

type T0 = LengthOfString<"foo"> // 3

The type must support strings several hundred characters long (the usual recursive calculation of the string length is limited by the depth of recursive function calls in TS, that is, it supports strings up to about 45 characters long).

解题思路

待补充

答案

type LengthOfString<S extends string> = number

验证

import type { Equal, IsTrue } from '@type-challenges/utils'

type cases = [
  IsTrue<Equal<LengthOfString<''>, 0>>,
  IsTrue<Equal<LengthOfString<'1'>, 1>>,
  IsTrue<Equal<LengthOfString<'12'>, 2>>,
  IsTrue<Equal<LengthOfString<'123'>, 3>>,
  IsTrue<Equal<LengthOfString<'1234'>, 4>>,
  IsTrue<Equal<LengthOfString<'12345'>, 5>>,
  IsTrue<Equal<LengthOfString<'123456'>, 6>>,
  IsTrue<Equal<LengthOfString<'1234567'>, 7>>,
  IsTrue<Equal<LengthOfString<'12345678'>, 8>>,
  IsTrue<Equal<LengthOfString<'123456789'>, 9>>,
  IsTrue<Equal<LengthOfString<'1234567890'>, 10>>,
  IsTrue<Equal<LengthOfString<'12345678901'>, 11>>,
  IsTrue<Equal<LengthOfString<'123456789012'>, 12>>,
  IsTrue<Equal<LengthOfString<'1234567890123'>, 13>>,
  IsTrue<Equal<LengthOfString<'12345678901234'>, 14>>,
  IsTrue<Equal<LengthOfString<'123456789012345'>, 15>>,
  IsTrue<Equal<LengthOfString<'1234567890123456'>, 16>>,
  IsTrue<Equal<LengthOfString<'12345678901234567'>, 17>>,
  IsTrue<Equal<LengthOfString<'123456789012345678'>, 18>>,
  IsTrue<Equal<LengthOfString<'1234567890123456789'>, 19>>,
  IsTrue<Equal<LengthOfString<'12345678901234567890'>, 20>>,
  IsTrue<Equal<LengthOfString<'123456789012345678901'>, 21>>,
  IsTrue<Equal<LengthOfString<'1234567890123456789012'>, 22>>,
  IsTrue<Equal<LengthOfString<'12345678901234567890123'>, 23>>,
  IsTrue<Equal<LengthOfString<'aaaaaaaaaaaaggggggggggggggggggggkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'>, 272>>,
  IsTrue<Equal<LengthOfString<'000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000'>, 999>>,
]

参考

无