Doesn't appear to distinguish extended mailboxes

[Qix-]

In an email address, you can have [email protected], where the mail is delivered to [email protected] and the mail server (generally) ignores the +bar.

It'd be great if this library could parse that portion of the email address, allowing consumers to reconstruct the base email address sans the extended mailbox label.

[jackbearheart]

This could be a nice feature. It looks like people sometimes call this "sub-addressing" or "tags". I assume that all servers implementing this implement it by "split on the first + sign". If anyone can point me to a reasonable spec/rfc on how sub-addressing works, we could add it to the library, but I'm hesitant to add a function where all it does is "split on the first + sign" without having some kind of standard. How would a consumer of the library use this reliably unless they know the receiving mail server's implementation?

So, until then, it's just:

> const local = addrs.parseOneAddress('[email protected]').local;
> local.substring(0, local.indexOf('+'));
'foo'

[taxilian]

The spec for subaddressing is RFC 5233: https://tools.ietf.org/html/rfc5233 -- it leaves a lot up to the implementor, but the most common use case that I have seen you can just split to the first plus sign, I believe.

[al45tair]

The separator character sequence is unspecified by the RFC (intentionally). I think the '+' syntax originated with Postfix; qmail supported '-' instead. Postfix is configurable and actually allows the specification of any character (set) you like; it doesn't support multi-character separators. Gmail I suspect only supports '+'.

One other comment I have is that I'd strongly discourage websites from attempting to strip subaddresses. If the user has given you a subaddress, they mean for you to use it, and you can't know in advance exactly how the subaddress is formatted or even if '+' is the delimiter. Separating out subaddresses might be a useful feature of an email parsing library where it's being used by mail clients or other user-side utilities, however.

[taxilian]

While I agree it's a bad idea to strip subaddresses there are still valid use cases -- I have a "global unsubscribe" option on my site and I prefer it to block the address totally, including any subaddresses.

[cmawhorter]

fwiw in addition to the plus, gmail strips out a subset of characters. for example [email protected] is the same as [email protected] and both deliver. i'd bet they allow [email protected] too but the gmail client doesn't