TypeScript 函数重载

export default class Test extends cc.Component{
	//#region 声明
	public foo():void;
	public foo(a:string,b:string):string;
	public foo(a:number,b:number):number;
	//#endregion
	
	//实现
	public foo(a?:string|number,b?:string|number):any{
		return null;
	}
}