implements類的函數(shù)重載需要在類中聲明與所實現(xiàn)接口一致的函數(shù)重載聲明【ts 4.1.3】

interface Test {
    t1(p: string): number;
    t1(p: number): string;
}

class TestClass implements Test {
    t1(p: string): number;
    t1(p: number): string;
    t1(p: string | number) {
        return typeof p === 'string' ? Number(p) : String(p);
    }
}