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conformance · v154

v154 · add-options-bag-to-websocket-constructor — conformance probe

6 assertions drawn from the spec. Each is a single contract the spec text makes. Pass/fail reflects what this browser executed; blocked means the contract was not run because it needs user mediation, hardware, or another unavailable precondition. Open the page in Chrome stable / canary / Firefox / Safari to compare.

browser: spec: https://github.com/whatwg/websockets/pull/76 chromestatus: #5080055102439424 generated 2026-08-28T04:20:00Z by claude-opus-5-v154-build
0
pass
0
fail
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blocked
6
total
id contract kind verdict detail
websocket-constructor-exists The interface this feature extends. spec ↗ typeof
constructor-reads-protocols-from-a-dictionary The feature itself: the constructor must read a `protocols` member off a dictionary passed as the second argument. A getter proves it was read, with no connection needed — before Chrome 154 the object was coerced to a subprotocol string instead. spec ↗ script
positional-string-still-works The 2011 form must keep working: a single subprotocol string opens a connection and negotiates it. spec ↗ script
positional-sequence-still-works So must the sequence form. The server prefers `echo` over `chat`, so offering both must negotiate `echo` — which also confirms the offer really reached the server. spec ↗ script
no-subprotocol-opens-cleanly Offering nothing is not an error: the connection opens with an empty protocol. Most sockets do not use one. spec ↗ script
duplicate-subprotocols-throw A repeated subprotocol is a SyntaxError at construction, before any network activity. This rule predates the feature and must survive it. spec ↗ throws