Are parameters optional in JavaScript?

Go does not have optional parameters nor does it support method overloading: Method dispatch is simplified if it doesn’t need to do type matching as well.

There are no optional parameters in Java . What you can do is overloading the functions and then passing default values.

In JavaScript, function parameters default to undefined . However, it’s often useful to set a different default value. This is where default parameters can help. In the past, the general strategy for setting defaults was to test parameter values in the function body and assign a value if they are undefined .

You should almost never use it as a field of something or a method parameter . So the answer is specific to Optional: it isn’t “a general purpose Maybe type”; as such, it is limited, and it may be limited in ways that limit its usefulness as a field type or a parameter type.

We can make a parameter optional by assigning default values for that parameter, like: