fix(subscription): allMids() never resolved (release 0.1.6)

[joeblau]

client.allMids() — with no arguments, or with dex: "" — never resolved. It rejected with WebSocketRequestError: Request timed out, or hung forever when timeout was null. Only a non-empty dex worked, so the main-dex mid-price feed — what almost every caller wants — was unusable in 0.1.5.

The chain

1. allMids.ts builds its payload as { type: "allMids", dex: params.dex || undefined }, so dex exists as an own key holding undefined.
2. normalize() walks Object.keys() and faithfully recreates that key, so the subscription's normalized form carries dex: undefined.
3. JSON.stringify drops it on the way out. The server receives {"type":"allMids"} and echoes back exactly that.
4. isSubset requires every key of the pending request to be present in the response (key in sup). It looks for a dex the server was never told about, finds nothing, and the subscription is never matched to its own confirmation.

Reproduced against a mock that echoes the subscribe frame verbatim:

allMids()             -> REJECTED: Request timed out after 3000 ms
allMids({dex:''})     -> REJECTED: Request timed out after 3000 ms
allMids({dex:'test'}) -> resolved OK

After the fix all three resolve and deliver frames to the listener.

Why the fix is in normalize()

A key whose value is undefined cannot survive serialization, so keeping it leaves the in-memory identity describing a request that was never sent. Dropping it makes the id, the echo, and the wire frame agree — and immunizes any future payload built with the same x || undefined shape. allMids is the only method using it today, so the blast radius is small either way, but the root cause is the normalizer, not the method.

Why no test caught it

The only allMids test is mode: "api" — it needs the live network and is skipped in the offline suite CI runs. So the bug sat in a path CI never exercised. The regression test added here covers the root cause and runs offline; I verified it fails against the unfixed normalize() and passes with it.

Provenance

Found while benchmarking this SDK against upstream @nktkas/hyperliquid, whose allMids works correctly. The divergence is ours, introduced in this fork.

bun run check exits 0; 1681 pass, 236 skip, 0 fail.

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