1、花括号对象通过方括号字符串形式取值
let obj = { name: 'asd', age: 21, salary: 400, desc: "asdasd", op: ['asd', 'as', 'qwe'] };for (let i in obj) {console.log(obj[i as keyof typeof obj]);
}let key = 'name';
console.log(obj[key as 'name']);
console.log(obj[key as keyof typeof obj]);2、泛型约束
// 函数泛型约束
interface limit<Y> {value: Y[];length: () => number;join: (str?: Y) => Y;
}
// 对T约束
function fun<Y, T extends limit<Y>>(params: T): Y {let res: Y = params.join();return res;
}// 定义对象类型
type Obj1Type = {value: string[],length: () => number,join: (v1?: string) => string
};
// 定义对象
const obj1: Obj1Type = {value: ['123', '456'],length() {return this.value.length;},join() {return this.value.join('');}
};const result1 = fun<string, Obj1Type>(obj1);console.log(result1);3、枚举
enum Fruits {Apple,Orange,Banana,Peach,Pear,Watermolen
}console.log(typeof Fruits[0], Fruits.Banana);// string, 2enum Fruits2 {Apple = '123',Orange = 'asd',Banana = '123t',Peach = '123d',Pear = 'asd',Watermolen = 'dasd'
}console.log(Fruits2.Banana);// 123tenum Fruits3 {Apple = 10,Orange,Banana,Peach = '123d',Pear = 'asd',Watermolen = 'dasd'
}console.log(Fruits3[10], Fruits3.Banana);// Apple,124、抽象类
abstract class Virtual {abstract name: string;abstract work(): void;
}class Human {}class Man extends Human implements Virtual {name;constructor(name: string) {super();this.name = name;}work() {}
}let m1 = new Man('Tom');5、函数重载
// 函数重载
function handleData(x: string): string[];function handleData(x: number): string;function handleData(x: any): any {if (typeof x === 'string') {return x.split(' ');} else if (typeof x === 'number') {return String(x);} else {return 'error!';}
}console.log(handleData(3),handleData('as asdd asd 34'));6、interface定义class的类型，interface继承
class Geometry {setAttribute() {}
}
//继承后 BoxGeometryType 要实现 Geometry的属性和方法
interface BoxGeometryType extends Geometry {width: number;height: number;depth: number;clone:()=>void;
}class BoxGeometry implements BoxGeometryType {width;height;depth;constructor(width: number, height: number, depth: number) {this.width = width;this.height = height;this.depth = depth;}clone(){}setAttribute() {}
}7、构造函数的定义、继承
interface FatherType {name: stringage: number;salary: number;print: () => void;getName: Function;
};function Father(this: FatherType, name: string, age: number, salary: number) {this.name = name;this.age = age;this.salary = salary;this.print = function () {console.log(this.name, this.age, this.salary);}
}
Father.prototype.getName = function () {console.log(this.name);
}interface SonType extends FatherType {name: string;getName: Function;father: () => void;
};Son.prototype = Object.create(Father.prototype);
Son.prototype.constructor = Son;function Son(this: SonType, name: string, father: { name: string, age: number, salary: number }) {Father.call(this, father.name, father.age, father.salary);this.name = name;
}Son.prototype.getName = function () {console.log(this, this.name);
}Son.prototype.father = function () {console.log(this);
}const son = new (Son as any)("Tom", { name: "Tom1", age: 21, salary: 123123 });
son.father();
son.getName();export default {};8、修饰器
在修饰器有：类修饰器、方法修饰器、参数修饰器、属性修饰器。
执行顺序：属性>方法>参数>类 。
1、类修饰器，可以在类上添加一些属性和方法
// example 1
const MessageDecorator: ClassDecorator = (target: Function) => {target.prototype.message = (msg: string) => {console.log(msg)}
}@MessageDecorator
class Login {public login() {(this as any).message('登录成功');(<any>this).message('登录成功');}
}new Login().login();// example 2
function Decorate(type: string) {if (type == '1') {return (target: Function) => {console.log(target);target.prototype.p0 = () => {console.log('p1');}}} else {return (target: Function) => {target.prototype.p0 = () => {console.log('p2');}}}
}@Decorate('1')
class P1 { }@Decorate('2')
class P2 { }const pa = new P1();
const pb = new P2();
(pa as any).p0();
(<any>pb).p0();2、 方法修饰器，可以修改被调用的函数，或者在被调用的函数调用前后做一些事情。
// example 1
const showDecorator:MethodDecorator=(target: Object, propertyKey: string | symbol, descriptor: PropertyDescriptor)=>{// 修改show函数descriptor.value=()=>{console.log('function changed.');}// 在外部不可以改// descriptor.writable=false;
}class User{@showDecoratorpublic show(){console.log('show???');}
}const u1=new User();
u1.show();// example 2
const sleep = (time: number): MethodDecorator => {return (...args: any[]) => {const [, , descriptor] = args;// 保存原函数const method = descriptor.value;console.log('first');descriptor.value = () => {setTimeout(() => {// 在此处调用原函数method();}, time);}}
}class Sleep {@sleep(1000)public show() {console.log('print something out.');}
}new Sleep().show();3、属性修饰器，可以用来控制类中属性的获取和修改
// example 1
const property: PropertyDecorator = (target: object, propertyKey: string | symbol) => {let value:string;Object.defineProperty(target,propertyKey,{get:()=>{return value.toLowerCase();},set:(v)=>{value=v;}});
}export class Hd {@propertypublic title?: string | undefined ='123';public show(value) {this.title=value;}
}const h=new Hd()
h.show("abcHAGKSDJkjnas");
console.log(h.title)// example 2
import 'reflect-metadata'function Inject(target: any, key: string) {// 根据A的类型进行实例化，并赋值到a，'design:type'自动获取固定名称，不需要自己defineMetadatatarget[key] = new (Reflect.getMetadata('design:type', target, key))();
}class A{sayHello(){console.log('hello');}
}class B {@Injecta!: A;say() {this.a.sayHello();}
}new B().say();4、 参数修饰器，一般与方法修饰器配合使用，在调用类方法前，对方法参数进行提前处理。
导入import 'reflect-metadata'可以在修饰器之间进行传值
Reflect.defineMetadata('required', requiredParams, target, propertyKey)；// 发送
let pArray=Reflect.getMetadata('required', target, propertyKey); // 接收
import 'reflect-metadata'const params: ParameterDecorator = (target: object, propertyKey: string | symbol, parameterIndex: number) => {let requiredParams: number[] = [];requiredParams.push(parameterIndex);Reflect.defineMetadata('required', requiredParams, target, propertyKey)
}const validate: MethodDecorator = (target: object, propertyKey: string | symbol, descriptor: PropertyDescriptor) => {console.log( 'method decorate params =',target, propertyKey,descriptor);let pArray=Reflect.getMetadata('required', target, propertyKey);console.log(pArray);const method=descriptor.value;descriptor.value=(...args)=>{console.log('args=',args,'pArray=',pArray);for(let i in pArray){args[pArray[i]]+='!!!';}method(...args);}}export class User {@validatepublic find(@params name: string,age:number) {console.log(name,age);}
};new User().find("abcdef",21); // abcdef!!! 21!!!
