interface Shape {
name: string;
width: number;
height: number;
color?: string;
}
function area(shape : Shape) {
var area = shape.width * shape.height;
return "I‘m " + shape.name + " with area " + area + " cm squared";
}
console.log( area( {name: "rectangle", width: 30, height: 15} ) );
console.log( area( {name: "square", width: 30, height: 30, color: "blue"} ) );
原文：https://www.cnblogs.com/montai/p/13356990.html