Add Label B9 ATIS Request decoder plugin

[thepacket]

Adds a decoder for label B9 D-ATIS requests (request for ATIS broadcast).

npm run build passes.

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Configuration used: Repository UI

Review profile: CHILL

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Run ID: 699c1c0b-a911-411e-8fa7-8a3512fa746d

📥 Commits

Reviewing files that changed from the base of the PR and between 10f9f69 and 737ca0d.

📒 Files selected for processing (3)

• lib/MessageDecoder.ts
• lib/plugins/Label_B9_ATIS_Request.ts
• lib/plugins/official.ts

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[kevinelliott]

Summary

Adds a new Label_B9_ATIS_Request plugin for label B9 D-ATIS request downlinks (/ICAO.TI2/SEQ ICAO LETTER SUBQ CHK). Registers it last in MessageDecoder.ts/official.ts. No companion test file.

Verdict

Comment-only review — needs changes before merge. The decoding logic is reasonable and self-contained, but there are no tests, no preamble qualifier (so the plugin runs against every B9 message even when it can't apply), and a couple of small data-model concerns.

Must Fix

• Add a Label_B9_ATIS_Request.test.ts. Every other label plugin in this directory has one and the project's review checklist explicitly flags missing tests. At minimum: qualifiers() shape, a happy-path decode for /EDDK.TI2/024EDDKA661A, the partial-header fallback, and a non-matching string.
• Restrict the qualifier to a real preamble. Right now qualifiers() returns labels: ['B9'] only — every B9 message is run through this regex even when it's clearly not a TI2 request. Add preambles: ['/'] (every observed shape begins with /) so the dispatcher can short-circuit. This is consistent with peers like Label_H1_Paren (preambles: ['(']).

Should Fix

• raw.arrival_icao = gs is semantically wrong. A B9 ATIS request targets a ground-station ATIS service — that station may or may not be the flight's arrival airport. Storing it under arrival_icao will pollute downstream consumers that aggregate by destination. Drop it; you already expose ground_station_icao and the top-level airport item under code: 'GNDSTN'. Same applies to the partial-header fallback path (line 67).
• decodeResult.formatted.items = [...] (line 111) replaces the array. It happens to be empty here because initResult() doesn't push anything, but the convention everywhere else in the codebase is items.push(...). Switching avoids a subtle footgun if initResult is ever extended.
• raw.checksum is typed number in RawFields but you assign a string. chk is [A-Z0-9]{2,4}, e.g. "661A". Either assign it under a different key (raw.atis_checksum_hex) or convert via parseInt(chk, 16). Today this just relies on the index signature falling through, but it'll trip up anyone reading types.

Nits

• The phonetic table is fine, but it's effectively a const map — pulling it out of the class avoids reallocating on every decode (cosmetic only).
• "differs from header" / "echoes target" annotation embedded in the value string is friendly but mixes data and presentation — fine for now, just be aware it makes programmatic comparison harder.
• The 2–4 char checksum window is wide; if you have a sample showing variable widths it would be nice to capture in a comment so future maintainers don't tighten it accidentally.

Tests

None added. Please add Label_B9_ATIS_Request.test.ts covering at minimum:

• qualifiers() shape (will need to be updated after adding the / preamble)
• Happy path (/EDDK.TI2/024EDDKA661A) — assert tail/letter/subq/checksum and the items array
• Partial-header fallback (/EDDK.TI2/...garbage)
• Non-matching string returns decoded: false

Notes — Registration & Coexistence

• Registered at the tail of pluginClasses in MessageDecoder.ts (after Label_QQ) and exported from official.ts. No other plugin claims label B9, so order is irrelevant.
• No coexistence concerns.

Thanks @thepacket!