:string):string{ if(lastName){ return fristName + lastName; }else{ return fristName; } } //传一个参数调用 let bob = buildName('bob'); console.log(bob); //传两个参数调用 let zhangsan = buildName('zhang','san'); console.log(zhangsan); 剩余参数,指参数在自定义时无法确定需要上送...
function getVersion(version:string) { if (!version) { version = "1.0.0"; } return version; } console.log(getVersion("1.0.1")); 使用常见配置选项 { "compilerOptions": { "target": "ES6", // 目标语言的版本 "removeComments": true, // 删除注释 "outDir": "./dist/", // 编译输出路...
constfullNameMaxLength=10;classEmployee{private_fullName:string="";getfullName():string{returnthis._fullName;}setfullName(newName:string){if(newName&&newName.length>fullNameMaxLength){thrownewError("fullName has a max length of "+fullNameMaxLength);}this._fullName=newName;}}letemployee=newEmp...
add(a: string, b: string): string; add(a: string, b: number): string; add(a: number, b: string): string; add(a: Combinable, b: Combinable) { if (typeof a === "string" || typeof b === "string") { return a.toString() + b.toString(); } return a + b; } } const ...
Alternatively, if you prefer to use the ActiveRecord implementation, you can use it as well:import { Entity, PrimaryGeneratedColumn, Column, BaseEntity } from "typeorm" @Entity() export class User extends BaseEntity { @PrimaryGeneratedColumn() id: number @Column() firstName: string @Column() ...
If the only known fact about the type is that it's some object, use the type object, not Object or { [key: string]: any }. var foo: string | any: When any is used in a union type, the resulting type is still any. So, while the string portion of this type annotation may ...
}elseif(typeofnickname ==='number') {console.log(`你的昵称是number类型${nickname}`) }else{thrownewError('请检查类型') } }checkNickname('赤蓝紫')checkNickname(123)checkNickname(true) 从上面的例子中,可以看到checkNickname只是接受string和number类型,当我们传boolean类型的时候,会在编译期间报错。
number//因为我们在下边有具体函数的实现,所以这里并不需要添加 declare 关键字//下边是实现function add (arg1:string| number, arg2:string|number) {//在实现上我们要注意严格判断两个参数的类型是否相等,而不能简单的写一个 arg1 + arg2if(typeofarg1 ==='string'&&typeofarg2 ==='string') {returnar...
class SafeBox { #value: string | undefined; // Only accepts strings! set value(newValue: string) { } // Must check for 'undefined'! get value(): string | undefined { return this.#value; } } In fact, this is similar to how optional properties are checked under --exactOptionalPrope...
As you note,Khas a purpose... to limit the property keys to particular values. If you want to accept all possible string-valued keys, you could do something likeRecord<string, T>, but the idiomatic way of doing that is to use anindex signaturelike{ [k: string]: T }. ...