interfaceAdmin{name:string;privileges:string[];}interfaceEmployee{name:string;startDate:Date;}type UnknownEmployee=Employee|Admin;functionprintEmployeeInformation(emp:UnknownEmployee){console.log("Name: "+emp.n
// interface通过extends实现继承interfaceuserName{name:string;}interfaceuserextendsuserName{age:number}letstu:user={name:'wang',age:10}// interface的extends扩展可以通过type交叉(&)类型实现type userName={name:string;}type user=userName&{age:number}letstu:user={name:'wang',age:18}// interface扩展ty...
Learn about interface in TypeScript. TypeScript interface is defined with 'interface' keyword and can include one or more methods or property declarations.
interface ISumFunc { (x: number, y: number): number; } let sum: ISumFunc = function (x, y) { return x + y; }; 同时可以使用含有泛型的接口来约束函数: interface CreateArrayFn { <T>(length: number, item: T): Array<T>; } let createList: CreateArrayFn; createList = function <T...
result.hasOwnProperty(id)) { (<any>result)[id] = (<any>second)[id]; } } return result; } class Person { constructor(public name: string) { } } interface Loggable { log(): void; } class ConsoleLogger implements Loggable { log() { // ... } } var jim = extend(new Person(...
functionextend<T,U>(first:T,second:U):T&U{constresult=<T&U>{};for(letpropinfirst){(<T>result)[prop]=first[prop];}for(letpropinsecond){if(!result.hasOwnProperty(prop)){(<U>result)[prop]=second[prop];}}returnresult;}letobj=extend({a:1},{b:2}); ...
Read onlyAdd the readonly keyword in front of the property name. Use this for properties that should only be modified when an object is first created.readonly firstName: string; Declare an interface with members Open thePlaygroundand remove any existing code. ...
Type又叫类型别名(type alias),作用是给一个类型起一个新名字,不仅支持interface定义的对象结构,还支持基本类型、联合类型、交叉类型、元组等任何你需要手写的类型。 type Num = number; // 基本类型 type StringOrNum = string | number; // 联合类型 ...
interface A { a: string; } interface B { b: string; } type MyType = A | B; function isA(x: MyType): x is A { return "a" in x; } function someFn(x: MyType) { if (isA(x) === true) { console.log(x.a); // works! } } We’d like to thank Mateusz Burzyński fo...
function extend<T, U>(first: T, second: U): T &U {constresult = <T & U>{};for(let propinfirst) { (<T>result)[prop] =first[prop]; }for(let propinsecond) {if(!result.hasOwnProperty(prop)) { (<U>result)[prop] =second[prop]; ...