fix(dash): [PKG-DASH-05] align nullable SDK metadata and validate real types

packages/artplayer-plugin-dash-control/ARCHITECTURE.md

@@ -73,6 +73,9 @@ the controlled error/identity tests. Changes to SDK capability detection belong
 `sdk.ts`, not in a global `any` or ambient module escape.
 
 Public `Config`, `Option`, `QualityLevel`, `AudioTrack`, and `Result` are named types.
+AudioTrack id/index/lang include null as declared by both actual SDK generations;
+internal AudioFields aliases that public shape. Nullable default labels preserve
+runtime behavior, while caller formatters must still return strings.
 Default callbacks infer known SDK fields; explicit generic parameters or callback
 annotations accept a caller's more detailed SDK interfaces. Original object-based
 formatters remain valid. The optional overload supports omitted/undefined options;
@@ -126,5 +129,9 @@ It also includes a native SDK control without an ArtPlayer instance. Early SDK 4
 paused-seek stalls remain open; later passes do not resolve them. Unsupported MSE is
 recorded as a playback capability gap, not acceptance. This plugin currently refreshes
 on ready/restart/explicit update, not automatically on external SDK events.
+`refactor/scripts/dash-sdk-types.test.mjs` compares actual SDK-only and plugin
+consumers across ten compiler/module configurations, retaining upstream-only
+Node10/old DOM diagnostics. The exact peer dependency closure is hash-pinned in
+`refactor/baselines/dash-type-dependencies.json`; no type shim or paths mapping is used.
 See [refactor validation](../../refactor/dash-validation.md) for baseline failures
 and [task plan](../../refactor/plan.md) for remaining type and release work.

packages/artplayer-plugin-dash-control/README.md

@@ -6,6 +6,27 @@ Accepts a caller-owned dash.js instance at `art.dash`. Quality selection adapts
 dash.js 4.x quality methods or 5.x representation methods. Version 5 selection uses
 representation IDs so bitrate filtering does not change the selected quality.
 
+## TypeScript
+
+The formatter receives the original SDK object. For dash.js 5.2.1 types:
+
+```ts
+import type { MediaInfo, Representation } from 'dashjs'
+import dashControl from 'artplayer-plugin-dash-control'
+
+dashControl<Representation, MediaInfo>({
+  quality: { getName: level => `${level.height}p` },
+  audio: { getName: track => track.lang || String(track.id) },
+})
+```
+
+dash.js 4.5.2 uses `BitrateInfo` for quality instead of `Representation`. Audio
+metadata `id`, `index`, and `lang` may be null; custom formatters must return strings.
+The original object-based formatters and synchronous `update()` remain supported.
+Actual 5.2.1 SDK types resolve with TypeScript 5.9.3 NodeNext/Bundler in our matrix;
+Node10 resolution and TypeScript 4.3.5 have upstream SDK declaration limitations.
+See the [tested type matrix](../../refactor/changes/2026-09-12-PKG-DASH-05-sdk-types.md).
+
 ## Demo
 
 [https://artplayer.org](https://artplayer.org/?libs=https://cdnjs.cloudflare.com/ajax/libs/dashjs/5.2.1/modern/umd/dash.all.min.js%0A./uncompiled/artplayer-plugin-dash-control/index.js&example=dash.control)

packages/artplayer-plugin-dash-control/src/types.ts

@@ -1,6 +1,6 @@
-import type { Config } from '../types/artplayer-plugin-dash-control'
+import type { AudioTrack, Config } from '../types/artplayer-plugin-dash-control'
 
-export type Label = string | number | undefined
+export type Label = string | number | null | undefined
 export type Identifier = string | number
 export type Valid = () => boolean
 export type Cleanup = () => void
@@ -12,11 +12,7 @@ export interface QualityFields {
   qualityIndex?: number
 }
 
-export interface AudioFields {
-  id?: Identifier
-  index?: number
-  lang?: string
-}
+export type AudioFields = AudioTrack
 
 export interface Dash<Level extends object = object, Track extends object = object> {
   getVideoElement: () => object | null

packages/artplayer-plugin-dash-control/types/artplayer-plugin-dash-control.d.ts

@@ -10,9 +10,9 @@ export interface QualityLevel {
 }
 
 export interface AudioTrack {
-  id?: string | number
-  index?: number
-  lang?: string
+  id?: string | number | null
+  index?: number | null
+  lang?: string | null
 }
 
 export interface Config<Item extends object = object> {