And that is why you extend the proposal.
This is how you get all aliases using your method:
JSON.parse(e.content).nip05_aliases
And this is how it works with NIP-39:
e.tags.filter(t => t[0] === "i").map(t => t[1].split(":")).filter(t => t[0] === "nip05").map(t => t[1])
Both fit in one line, and the latter allows you to also support PGP keys and similar