new.ts

/**
 * @description 实现一个new方法
 * @author tangc1
 * @date 2022-04-21 21:05:52
*/

exportfunctioncustomNew<T>(constructor: Function, ...args: any[]): T{
// 1. 创建一个空对象，继承constructor的原型
constobj=Object.create(constructor.prototype)
// 2. 将obj作为this，执行constructor，并传入参数
constructor.apply(obj,args);
// 3. 返回obj
returnobj
}

classFoo{
name: string
age: number
city: string
constructor(name: string,age: number,city: string){
this.name=name
this.age=age
this.city=city
}

getName(){
returnthis.name
}

getAge(){
returnthis.age
}

getCity(){
returnthis.city
}
}
// const f = new Foo('zhangsan', 18, 'changsha')
constf=customNew<Foo>(Foo,'zhangsan',18,'changsha')
console.info(typeoff);
console.info(typeofFoo);
console.info(f);
console.info(f.getCity());