36. KebabCase

[astak16]

题目

题目链接：KebabCase，答题

实现 KebabCase，满足下面需求

import type { Equal, Expect } from "@type-challenges/utils";

type cases = [
  Expect<Equal<KebabCase<"FooBarBaz">, "foo-bar-baz">>,
  Expect<Equal<KebabCase<"fooBarBaz">, "foo-bar-baz">>,
  Expect<Equal<KebabCase<"foo-bar">, "foo-bar">>,
  Expect<Equal<KebabCase<"foo_bar">, "foo_bar">>,
  Expect<Equal<KebabCase<"Foo-Bar">, "foo--bar">>,
  Expect<Equal<KebabCase<"ABC">, "a-b-c">>,
  Expect<Equal<KebabCase<"-">, "-">>,
  Expect<Equal<KebabCase<"">, "">>,
  Expect<Equal<KebabCase<"😎">, "😎">>
];

答案

方法一

type KebabCase<T> = T extends `${infer FirstLetter}${infer RestLetter}`
  ? Rest extends Uncapitalize<Rest>
    ? `${Uncapitalize<FirstLetter>}${KebabCase<RestLetter>}`
    : `${Uncapitalize<FirstLetter>}-${KebabCase<RestLetter>}`
  : T;

知识点

1. 把字符串拆分成两部分：FirstLetter 和 RestLetter
2. 这里不在是判断 FirstLetter 部分，而是判断 RestLetter 部分首字母是否大写

• 看题意，需要把大写字母变成小写，并且在它前面增加 -
• 如果判断 FirstLetter，那单词首字母大写的话，就会在单词前面添加 - 不符合题意