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I am trying to find the perfect regex that will help me extract the domain name of an email. (ex: [email protected] should return domain.com)

A lot of issue on SO address this problem but none of them treat it perfectly.

Here are the special edge cases that I want to tackle:

  1. I don't want to keep subdomains. (ex: [email protected] should return domain.com )
  2. Some domain extensions have two dots. (ex: [email protected] should return domain.co.uk)
  3. It is possible to include an at (@) in your domain name (although most registrar do not allow it). (ex: hello@[email protected] should return [email protected])

I have tried the following regex but they don't tackle all the edge cases:

  • /(?<=@)\S+\.\S+$/ => Does not handle case 1
  • /[^.@]*?\.\w{2,}$|[^.@]*?\.com?\.\w{2}$/ => Does not handle case 3
nsayer
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  • *"I don't want to keep subdomains. (ex: `[email protected]` should return `domain.com` )"* if you don't want subdomains, it should return `com` – Cid Sep 13 '21 at 16:20
  • Your case 3 would be interpreted by an email system as user "hello@dom" on domain "in.com"; multiple @ symbols are allowed in email addresses but the last one is the domain separator. https://stackoverflow.com/questions/12355858/how-many-symbol-can-be-in-an-email-address – Daniel Beck Sep 13 '21 at 16:20
  • ...actually on rereading I'm realizing it wouldn't be a valid email address at all, unless it were literally `"hello@dom"@in.com` (quotes included) – Daniel Beck Sep 13 '21 at 16:22
  • You are missing other edge cases, such as `[email protected]` – Cid Sep 13 '21 at 16:24
  • @cid, then i want want to keep the first level domain. – nsayer Sep 13 '21 at 16:25

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