ArtPlayer/packages/artplayer-plugin-danmuku/ARCHITECTURE.md

Danmuku maintenance map

The compatibility reference is the actual npm 5.3.0 package. Its archive, historical declarations, earlier exports and failure evidence are indexed in refactor/baselines/danmuku-release.json and danmuku-contract.md at the repository root. Do not infer runtime contracts from the old declaration file.

Module responsibilities

Module	Responsibility
src/index.js	Plugin factory, facade getters, bound methods, setting and heatmap composition
src/danmuku.js	Internal instance, public method return identity, queue commits and events; scheduling is still here pending PKG-DANMUKU-04
src/config.js	Fresh defaults, validation schema, configuration comparison and normalization
src/input.js	Input forms, replacement ownership, independent append operations, cancellation and synchronous callback reentry
src/bilibili-parser.js	Pure legacy-compatible XML fields, mode mapping and entity decoding
src/bilibili.js	Fetch and response text, one parser Worker per request, fallback, settlement and Blob URL cleanup
src/worker.js	Track placement Worker; a separate protocol from the XML parser Worker
src/setting.js	Settings and emitter UI; lifecycle restructuring follows in PKG-DANMUKU-05
src/heatmap.js	Heatmap rendering; restructuring follows in PKG-DANMUKU-05

The package is undergoing staged migration. PKG-DANMUKU-03 separates input and configuration responsibilities in JavaScript; PKG-DANMUKU-06 converts all owned modules and Worker messages to TypeScript and validates installed consumers. This intermediate structure is not the final TypeScript or release acceptance.

Contracts to retain

• The registrar returns its facade synchronously. emit() and load() return Promises resolving to the internal Danmuku instance, which differs from that facade. config/hide/show/reset return that same internal instance synchronously; mount() returns undefined. Keep the three live getters.
• load() and load(undefined) replace only after input succeeds. load(target) appends without updating option.danmuku. Independent appends may complete in either order and can append after a replacement.
• Arrays enter synchronously. Empty initial input emits show -> config -> reset -> loaded before registration returns. Nonempty input inserts the first item before the first await, then awaits each emit() in order. A later invalid item leaves earlier accepted items present.
• A new replacement supersedes an older replacement. Destroy cancels all input operations. Cancelled public loads resolve to the same internal instance; they do not emit late loaded/error events or write stale rows. The input Promise itself may be uncancellable; observe its eventual rejection locally.
• Invoke a loader function without an explicit receiver. Invoke the filter through the current option so its receiver remains that option. Check load ownership again after callbacks and reset events, including synchronous callbacks that start another replacement.
• Keep input normalization observable: accepted objects receive missing mode, style and color before filtering, and the queue receives a shallow copy. Explicit time zero is preserved; missing time defaults to current time + 0.5, and negative time is clamped to zero.
• Function and Promise configuration changes use identity. Structurally equal ordinary values retain the historical JSON comparison behavior. Validate and normalize a prospective option before replacing the current option; invalid updates cannot corrupt it. Configuration does not implicitly reload input.
• Keep XML entity order, unpadded hexadecimal colors, numeric conversions, extension fields and existing mode mapping. An empty XML document is a valid empty result. Fetch/text failures must reach the public load's single error outlet and reject it; automatic initial loading observes that rejection.

Verification and remaining work

yarn test:danmuku runs frozen historical contracts/failures and candidate input and parser regressions. The historical helper and archives must remain frozen; candidate tests use test/helpers/danmuku-candidate.js and may select built artifacts through ARTPLAYER_DANMUKU_ARTIFACT.

test/browser/danmuku-input.spec.js uses native video and Blob Workers against published and candidate cores. Run its source, main and legacy variants after the normal package build. Browser evidence distinguishes local XML/fault fixtures from the real Bilibili service, and Windows WebKit from Safari devices.

The older native track-overlap observation remains open until scheduler and rendering work is verified. A passing input test is not evidence that duplicate RAF loops, visibility continuations, settings cleanup, heatmap sampling or long-run load behavior have been fixed. See PKG-DANMUKU-04/05/07 and the risk register before changing completion or release status.