00019-medium-trim-right

[yunliuyan]

Trim Right

by Yugang Cao @Talljack

   

实现 TrimRight<T> ，它接收确定的字符串类型并返回一个新的字符串，其中新返回的字符串删除了原字符串结尾的空白字符串。

例如

type Trimed = TrimRight<'  Hello World  '> // 应推导出 '  Hello World'

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相关挑战

[yunliuyan]

思路

关键要判断右侧是否全是空字符串

代码实现

type IsEmptyStr<S extends string> = S extends '' ? true : S  extends ` ${infer R}` ? IsEmptyStr<R> : false;

type TrimRight<S extends string> = S extends IsEmptyStr<S> ? '' : S extends `${infer L} ${infer R}` ? IsEmptyStr<R> extends true ? L : `${L} ${TrimRight<R>}` : never;

type Trimed = TrimRight<'  Hello World  '> // 应推导出 '  Hello World'

[Janice-Fan]

type TrimRight<T extends string> = T extends `${infer F}${' ' | '\t' | '\n'}` ? TrimRight<F> : T;

type Trimed = TrimRight<'  Hello World  '> // 应推导出 '  Hello World'

[liangchengv]

type TrimRight<T> = T extends `${infer U}${' '}` ? TrimRight<U> : T;

type Trimed = TrimRight<'  Hello World  '>