在这种情况下,Record<Keys, Type> 可以用来定义角色和权限的类型,从而确保整个应用程序的类型安全。 代码语言:javascript 代码运行次数:0 运行 AI代码解释 // 定义一组角色type UserRole='admin'|'editor'|'viewer';// 定义权限为结构化对象type Permission={canCreate:boolean;canR
AI代码解释 //构建函数工厂declarefunctioncreate<Textendsnew()=>any>(c:T):InstanceType<T>;classYidengA{}classYidengB{}leta1=create(YidengA);// YidengAletb1=create(YidengB);// YidengB 5. NonNullable:从类型中排除null和undefined 代码语言:javascript 代码运行次数:0 运行 AI代码解释 //type TNon ...
function createUserId(name: string, id: number): string { return name + id; } IdGenerator = createUserId; 7.5 可选参数及默认参数 // 可选参数 function createUserId(name: string, id: number, age?: number): string { return name + id; } // 默认参数 function createUserId( name: stri...
The Pick type in TypeScript allows us to create a new type by selecting specific properties from an existing type. When combined with the Record type, it becomes a powerful tool for creating dictionaries with only a subset of properties. Suppose we have a CourseInfo interface with several prop...
The key idea of this feature is to make it easy for decorators to create and consume metadata on any class they’re used on or within. Whenever decorator functions are used, they now have access to a new metadata property on their context object. The metadata property just holds a simple...
Record Record的作用是允许从联合类型中创建一个新的类型,联合类型中的值作为新类型的属性。使用场景:接口类型声明。 type Record<K extends keyof any, T> = { [P in K]: T; }; type DepartName = 'grade' | 'office' | 'class' type DepartList = Record<DepartName, {id: number}> ...
(常见的) */objArr: {id: string;title: string;}[];/** 具有任意数量的相同类型属性的 dict 对象 */dict1: {[key: string]: MyTypeHere;};dict2: Record<string, MyTypeHere>; // 相当于 dict1/** 任何函数,只要你不调用它(不推荐) */onSomething: Function;/** 不接受或不返回任何内容的...
typeColors="red"|"green"|"blue";typeRGB= [red:number,green:number,blue:number];constpalette = {red: [255,0,0],green:"#00ff00",bleu: [0,0,255]// ~~~ The typo is now caught!}satisfiesRecord<Colors,string|RGB>;// Both of these methods are still accessible!constredComponent = pa...
B ='bbb'}letobj: Record<string,number> = { [Test.A]:1,// 枚举中的字符串值[Test.B]:2,// 枚举中的字符串值['value']:3// 字符串字面量} 相关约束 不支持Symbol() API 不支持通过索引访问字段 不支持delete运算符 仅允许在表达式中使用typeof运算符 ...
为了方便我们定义一个构造函数 createClock,它用传入的类型创建实例。 interface ClockConstructor { new (hour: number, minute: number): ClockInterface; } interface ClockInterface { tick(); } function createClock(ctor: ClockConstructor, hour: number, minute: number): ClockInterface { return new ctor(...