typescript函数的返回类型是否可以由参数确定

function getType(arg: string): string;
function getType(arg: number): number;
function getType(arg: boolean): boolean;

function getType(arg: any): any {
  return typeof arg;
}

const strType = getType("hello"); // 返回类型为string
const numType = getType(10); // 返回类型为number
const boolType = getType(true); // 返回类型为boolean

type ReturnType<T> = T extends string ? string :
                     T extends number ? number :
                     T extends boolean ? boolean :
                     any;

function getType<T>(arg: T): ReturnType<T> {
  return arg;
}

const strType = getType("hello"); // 返回类型为string
const numType = getType(10); // 返回类型为number
const boolType = getType(true); // 返回类型为boolean