the array elements are separated with a comma. */ join(separator?: string): string; ...
private 和 protected。 public: 默认的修饰符,它表示属性或方法是公有的,可以在类的内部和外部被访问。 private: 表示属性或方法是私有的,只能在类的内部被访问,外部无法访问。 protected: 表示属性或方法是受保护的,只能在类的内部及其子类中被访问,外部无法访问。 1.private 修饰符 示例: classPerson{privatenam...
join(separator?: string): string; let array: Array<string> = ["a","b","c","d","c","a"]; let result = array.join(); console.log(result); ? ? ? ? ? ?// a,b,c,d,c,a result = array.join("+"); console.log(result); ? ? ? ? ? ?// a+b+c+d+c+a result = ...
TypeScript 代码最终都会被编译成 JavaScript 代码来运行。这个编译的过程需要使用 TypeScript 编译器,我们可以为该编译器配置一些编译选项。 在TypeScript 项目的根目录下执行 “tsc-init” 命令,快速创建一个 tsconfig.json 文件。该文件用于配置 TypeScript 编译项目时编译器所需的选项。下面是该配置文件中比较常见的...
:T[];/***Addsalltheelementsofanarrayintoastring,separatedbythespecifiedseparatorstring.*@paramseparatorAstringusedtoseparateoneelementofthearrayfromthenextintheresultingstring.Ifomitted,thearrayelementsareseparatedwithacomma.*/join(separator?:string):string;}泛型类类的定义中带有类型参数，该类就...
列表: list(),列表是一个可迭代对象,常用的操作有for, join, sort, reverse, sorted, 索引和切片。...它本身有的操作包括: box = list() 或 box = [] 设置空的列表 box.append('value') 尾部追加元素 box.insert(1, 'value') 索引插入元素 box...索引替换或写入元素 box.pop() 删除尾部元素 box...
join() Joins all elements of an array into a string. 7. lastIndexOf() Returns the last (greatest) index of an element within the array equal to the specified value, or -1 if none is found. 8. map() Creates a new array with the results of calling a provided function on every...
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typescript复制代码function reverse(x: number | string): number | string { if (typeof x === 'number') { return Number(x.toString().split('').reverse().join('')); } else if (typeof x === 'string') { return x.split('').reverse().join(''); } } console.log(reverse(123)...
interface A {one: number;two: number;}interface B {three: number;four: number;}type Union = A | B;function func(x: Union) {// @ts-expect-error: Property 'two' does not exist on type 'Union'.// Property 'two' does not exist on type 'B'.(2339)console.log(x.two); // error...