import "reflect-metadata";

function logParamTypes(target: any, key: string) {
    var types = Reflect.getMetadata("design:paramtypes", target, key);
    var s = types.map(a => a.name).join();
    console.log(`${key} param types: ${s}`);
}

class Foo { }
interface IFoo { }

class Demo {
    @logParamTypes // apply parameter decorator
    doSomething(
        param1: string,
        param2: number,
        param3: Foo,
        param4: { test: string },
        param5: IFoo,
        param6: Function,
        param7: (a: number) => void,
    ): number {
        return 1
    }
}