Using optional arguments of overloaded TypeScript methods

I'm using a package written in TS in a JS app. I have a method with multiple overloads:

overloadedMethod(stringParameter: string): void;
overloadedMethod(stringParameter: string, otherParameter: any): void;

And I call it like this:

if (!myOtherParameter) {
    overloadedMethod(myStringParameter)
} else {
    overloadedMethod(myStringParameter, myOtherParameter)
}

I do not like this one bit. Have I approached the problem incorrectly, or is there some way I can include the otherParameter only if it is not undefined or null?