Parse area code out of phone number

Question

I have a list of phone numbers which are formatted in multiple ways such as: (212)-555-1234 or 212-555-1234 or 2125551234.

Using JavaScript, what would be the best way to extract only the area code out of these strings?

Answer 1

First, remove everything that is not a digit to get the plain number. Then, get the first three digits via slicing:

return myString.replace(/\D/g,'').substr(0, 3);