type C = FirstChar<"">; // never 1. 2. 3. 4. 5. 3. 获取字符串最后一个字符 LastChar export type LastChar<T, F extends string = ""> = T extends `${infer L}${infer R}` ? LastChar<R, L> : F; type A = LastChar<"BFE">; // E type B = LastChar<"Echoyya">; //...
2. 获取字符串第一个字符 FirstChar exporttypeFirstChar<T> = Textends`${infer L}${infer R}`? L :never;typeA =FirstChar<"BFE">;// 'B'typeB =FirstChar<"Echoyya">;// 'd'typeC =FirstChar<"">;// never 3. 获取字符串最后一个字符 LastChar exporttypeLastChar<T, Fextendsstring="...
U : never;//示例type result0 = InferArray<[number,string]>;//string | numbertype result1 = InferArray<string[]>;//stringtype result2 = InferArray<number[]>;//number 🐹 推断数组(或者元组)第一个元素的类型 定义: type InferFirst<T extends unknown[]> = T extends [infer P, ...infer...
[char, ...StringToArray<rest>] : []; type ret = StringToArray<"Hello World">; // type ret = ["H", "e", "l", "l", "o", " ", "W", "o", "r", "l", "d"] 数组、元组类型 数组匹配就是按位匹配,如果不确定是第几位就需要用...运算符处理。 取数组第一位 type GetFir...
const lowerString = aString.toLowerCase().split(' ').join('') // 加入队列 for (let i = 0; i < lowerString.length; i++) { deque.addBack(lowerString[i]) } let isEqual = true let firstChar = '' let lastChar = '' while (deque.size() > 1 && isEqual) { ...
type ReplaceAll<S extends string, From extends string, To extends string> = From extends '' ? S : S extends `${infer First}${From}${infer Last}` ? `${First}${To}${ReplaceAll<Last, From, To>}` : S; 单次替换的时候移除第四行的递归即可,千万注意不要对已经处理过的字符串再进行递归...
functionthrowError(){thrownewError();}functionfirstChar(msg:string|undefined){if(msg===undefined)throwError();letchr=msg.charAt(1)// Object is possibly 'undefined'.} 由于编译器不知道 throwError 是一个无返回的函数,所以throwError()之后的代码被认为在任意情况下都是可达的,让编译器误会 msg 的类...
#name:string; constructor(name:string) { this.#name=name; } equals(other:unknown) { returnother&& typeofother==="object"&& #nameinother&&// <- this is new! this.#name===other.#name; } } One interesting aspect of this feature is that the check#name in otherimplies thatothermust ha...
String Length and Access lettext ='TypeScript';// Get string lengthletlength: number = text.length;// 10// Access individual charactersletfirstChar: string = text[0];// 'T'letlastChar: string = text[text.length -1];// 't'Code language:JavaScript(javascript) ...
Head]&number>,Tail]:[Identifier<Head&string>,Tail]:[Identifier<T&string>,''];typeParseMember...