regex - Match only if not preceded or followed by a digit

Question

I have this regular expression to look for phone numbers in a codebase:

\d{3}[.s-]?d{3}[.s-]?d{4}g

How can I modify this so that it will not match instances where the number is preceded or followed by a digit?

18005555555 (should not match)
80055555551 (should not match)
"8005555555" (should match)
s800-555-5555 (should match)
8005555555 (should match)
800.555.5555 (should match)

Edit: I'm not trying to "match the whole word", because it is not sufficient that the match is preceded by and followed by a space. See the 3rd example of above that should also return a match.

I want to match only instances where the match is not preceded or followed by a digit.

In others words:

[NOT DIGIT][PHONE NUMBER][NOT DIGIT]

Answer 1

Lookahead and lookbehind will help you with these restrictions - if they are supported, like

/(?<!d)d{3}[.s-]?d{3}[.s-]?d{4}(?!d)/g

You can replace the lookbehind (?<!d) with (?:^|D) if it is not supported. You can replace the lookahead (?!d) with (?:D|$) if it is not supported.

You can find a demo here: https://regex101.com/r/aS8jQ8/1