(function () {
    // 泛型：先用字符去指代未知类型 使用时 传入具体的类型
    function fn3<T>(x: T): T {
        return x;
    }
    fn3(12);
    fn3<string>("12");

    // function fn4<T extends number | string, K extends number | string>(x: T, y: K): number | string {
    //     return x + y;
    // }
    function fn4<T, K>(x: T, y: K): string | number {
        return (x as number) + (y as string)
    }

    function fn5<T, K>(x: T, y: K): [T, K] {
        return [x, y];
    }
    fn5(3, '43')
    const res = fn4(3, '23');
    console.log(res, '22222')

    interface happy {
        jump: string
    }
    // 严格按照接口格式传参
    // 函数中泛型继承接口
    function fn6<T extends happy>(a:T):T {
        return a;
    }
    fn6({jump: 'aa'})
    // 类中泛型继承接口
    class Ending<T extends happy>{
        name:T;
        constructor(name:T) {
            this.name = name;
        }
    }
    let e = new Ending({jump: 'aa'})
})()