Question

我正在尝试为我的项目添加一个构造函数接口，并且为什么下面的代码没有抛出错误我感到非常困惑：

interface PointConstructor{
    new(x:number, y:number, z:number):point;
}

interface point{
    x:number;
    y:number;
    z:number;

    move_1();

}

class TwoDPoint implements point{
    x: number;
    y: number;
    z: number;
    constructor(x:number, y:number){
        this.x = x;
        this.y = y;
    }

    move_1(){
        this.x =this.x + 1;
        this.y = this.y + 1;        
    }
}

class ThreeDPoint implements point{
    x: number;
    y: number;
    z: number;
    constructor(x:number, y:number, z:number){
        this.x = x;
        this.y = y;
        this.z = z;
    }

    move_1(){
        this.x++;
        this.y++;
        this.z++;
    }
}

class improperpoint implements point{
    x: number;
    y: number;
    z: number;

    move_1(){
        this.x++;
        this.y++;
        this.z++;   
    }   
}

function constructPoint(ctor:PointConstructor, x:number,y:number, z:number=0):point{
    return new ctor(x,y,z);
}

let a = constructPoint(TwoDPoint, 0,0)
let b = constructPoint(ThreeDPoint, 0,0,0);
let c = constructPoint(improperpoint, 0,0,0);


console.log(`Point x ${a.x} Point Y ${a.y} Point z ${a.z}`);
console.log(`Point x ${b.x} Point Y ${b.y} Point Z ${b.z}`);
a.move_1()
b.move_1();

console.log(`Point x ${a.x} Point Y ${a.y} Point z ${a.z}`);
console.log(`Point x ${b.x} Point Y ${b.y} Point Z ${b.z}`); x ${b.x} Point Y ${b.y} Point Z ${b.z}`);

在前面的代码中，我期望不正确的实例化会抛出错误，因为它没有所需的构造函数接口。我做错了什么？

Answer 1

以下是代码的简化版本，显示了您预期错误的位置：

interface PointConstructor {
    new (x: number): Point;
}

interface Point {
    x: number;
}

class ImproperPoint implements Point {
    x: number;
}

let ctor: PointConstructor = ImproperPoint; // You expect an error here

它没有错误的原因是因为可以使一个函数占用比TypeScript中提供的更少的参数。

这是为了方便起见。否则，即使您不需要使用(evt)=>

，您也需要为事件处理程序之类的东西做evt。

window.addEventListener('resize',()=>{}); // This is an allowed use

围绕构造函数接口的混乱，为什么以下代码不会产生错误？

1 个答案: