Become RFC 5322-compliant

[Richienb]

The perfect email regex

It turns out that the parts of rfc 5322 responsible for defining what an email is, can be cross-compiled 1:1 to regex. At some point I will publish this abnf to regex converter (update: published at https://github.com/Richienb/abnf-regex). (I am also waiting for this PR which would improve the optimisation phase DmitrySoshnikov/regexp-tree#269)

TODO:

• Seperate out repetitive parts
• Add option to allow &? Add option to allow & #15
• Add option to allow domain part with only 1 part? This string passes as an exact match: '<[email protected]>' #2 (comment)

Fixes #9, fixes #2, fixes #15

[Richienb]

Should hopefully be non-breaking
If it were breaking, maybe also disallow &amp by default, which would be my preference. It would also make it RFC 5322 compliant.

[Richienb]

Added TypeScript devdep to make tests pass
Won't be needed in later versions of xo that support newer versions of Node

[Richienb]

Regex is now quite large
Could be fixed by adding options that disable other features

[sindresorhus]

If it were breaking, maybe also disallow &amp by default, which would be my preference. It would also make it RFC 5322 compliant.

Yeah, let's disable that by default. I will do a major version anyway.