The reg exp is : /\d-\d{3}-\d{3}-\d{4}/
1-444-666-8888 is a valid pattern
a-44-777-9999 is an invalid pattern

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the reg exp is /(\d{2,4}|[a-f]{2})-\d+/
w-8888 is an invalid pattern
44-99999 is a valid pattern