typescript - 继承接口

interface Shape {
    color: string;
}

interface Square extends Shape {
    length: number
}

let square = {} as Square;
square.color = "blue";
square.length = 10

一个接口也可以继承多个接口，如：

interface Shape {
    color: string;
}

interface Pen {
    width: number;
}

interface Square extends Shape, Pen {
    length: number
}

let square = {} as Square;
square.color = "blue";
square.width = 100;
square.length = 200;