0003. The Server url argument is required

Status: Accepted · 2026-07-28 · #64 Governed by: 0000

TL;DR new Server(url) requires its url; there is no argument-less form. smocket keeps a Map from origin to server and normalizes every connect(url) to an absolute url before lookup, so the required argument and that registry are one decision recorded together.

Decision

The url passed to new Server(url) is required. socket.io always takes a connection argument, even with a single server in play, and offers no argument-less form, so smocket requires one too. Making it optional would force an invented rule for what "two unlabelled servers" mean, a question socket.io never has to answer.

The required url implies a registry, so the two live in one file. smocket keeps a Map from origin to Server, and connect(url) finds its server by looking the normalized origin up in that map. Because a server is always keyed by a concrete url, the map needs no fallback entry for a missing one.

Normalization matches socket.io's own url.js: a relative path resolves against location.origin, and a missing port is filled from the scheme, http to 80 and https to 443, so two urls naming the same origin resolve to one key.

Alternatives rejected

• Make the url optional or default it. socket.io has no argument-less connection, so a default has no source to copy, and it would need an invented rule to disambiguate two servers created without a url.
• Skip normalization and key on the raw string. Two spellings of one origin, a bare host and the same host with its default port, would then miss each other in the map and split one server into two.