typescript 如何给Class中所有参数加上可选？

Question

class A = {
  a: numebr = 0;
  b: string = 'aa';
}

class B extends A{
  c:string = "2312"
}

B继承A的时候是否可以将A中的参数快捷设置为可选？

使用type中的Partial<Type>方法不适用于Class

Answer 1

class A {
  a: number = 0;
  b: string = 'aa';
}

class B extends ({} as new () => Partial<A>) {
  c: string = "2312"
}

参考：StackOverflow - Typescript class extending Partial interface

Answer 2

class A {
    a: number = 0;
    b: string = 'aa';
}

interface AProps {
    a?: number;
    b?: string;
}

class B extends A {
    c: string = "2312";

    constructor(props?: AProps) {
        super();
        if (props) {
            if (props.a !== undefined) this.a = props.a;
            if (props.b !== undefined) this.b = props.b;
        }
    }
}

const obj = new B({ a: 5 });
console.log(obj.a);  // 5
console.log(obj.b);  // 'aa'
console.log(obj.c);  // '2312'