Validate US Telephone Numbers (Freecodemap advanced algorithm 1)

If the incoming string is a valid US phone number, it is returned true .

Users can fill out a form with any valid US phone number. Here are some examples of valid numbers (as well as some variants to use when testing below):

555-555-5555 (555) 555-5555 (555) 555-5555555 555 555555555555551 555 555 5555

In this section you will see strings such as 800-692-7753 or 8oo-six427676;laskdjf . Your task is to verify that the string given above is a valid US phone number. The area code is a must. If the country codes are given in the string, you must verify that they are 1 . Returns if the number is valid true ; Back false .

It needs to be done using regular expressions.

function Telephonecheck (str) {  var reg =/^1?? \d{3}|\ (\d{3}\)) [-]?\d{3}[-]?\d{4}$/;  return Reg.test (str);}
Telephonecheck ("555-555-5555");

(\d{3}|\ (\d{3}\))     --555 or (555) of the form.

Validate US Telephone Numbers (Freecodemap advanced algorithm 1)