You can call it like this:
testObj.callableFunction && testObj.callableFunction();
or in details:
if (typeof testObj.callableFunction == 'function') {
testObj.callableFunction();
}
You can call it like this:
testObj.callableFunction && testObj.callableFunction();
or in details:
if (typeof testObj.callableFunction == 'function') {
testObj.callableFunction();
}