RegExp Format To Only Validate (###) ###-#### In Form?

I am working on a form that gets validated both on change and on submit (assignment). For the phone number, I want to validate so that the form will ONLY accept numbers entered in the following format: (###) ###-####
(ex. (555) 867-5309 ). I am new to JS, but am pretty sure this can be accomplished via using and comparing a regExp? If so, what is the code for that?

The closest one I can find is the following:
^(()?(787|939)()|-)?([0-9]{3})(-)?([0-9]{4}|[0-9]{4})$

Obviously, I do not only want to limit it to 787 or 939, so I need to remove that). Although, this accepts a variety of options that I do not want, like no parenthesis, only two numbers for area code, or no dashes, etc. I sort of understand how this works, but am unsure how to make the elements in the format REQUIRED as opposed to optional