docs(dash): [SITE-DASH-01] add bilingual guides and fix example lifecycle

test/dash-example.test.js

@@ -0,0 +1,79 @@
+import assert from 'node:assert/strict'
+import fs from 'node:fs'
+// eslint-disable-next-line test/no-import-node-test -- Execute the actual public example with a controlled SDK lifecycle.
+import { test } from 'node:test'
+import { runInNewContext } from 'node:vm'
+
+const source = fs.readFileSync(new URL('../docs/assets/example/dash.control.js', import.meta.url), 'utf8')
+
+function loadExample(supported) {
+  const engines = []
+  const hooks = []
+  const pluginOptions = []
+  const dashjs = {
+    supportsMediaSource: () => supported,
+    MediaPlayer: () => ({ create() {
+      const engine = {
+        destroyed: 0,
+        initialize(video, url, autoplay) {
+          Object.assign(this, { video, url, autoplay })
+        },
+        destroy() { this.destroyed++ },
+      }
+      engines.push(engine)
+      return engine
+    } }),
+  }
+  class Artplayer {
+    constructor(option) {
+      this.option = { autoplay: false, ...option }
+      this.notice = {}
+    }
+
+    on(event, callback) { hooks.push({ event, callback }) }
+  }
+  const sandbox = { Artplayer, dashjs, artplayerPluginDashControl: (option) => {
+    pluginOptions.push(option)
+    return () => ({})
+  } }
+  runInNewContext(`${source}\nglobalThis.exampleArt = art`, sandbox)
+  const art = sandbox.exampleArt
+  const video = {}
+  return { art, engines, hooks, pluginOptions, video, load: url => art.option.customType.mpd(video, url, art) }
+}
+
+test('DASH example releases replaced engines once and has one final cleanup hook', () => {
+  const example = loadExample(true)
+  for (const url of ['first.mpd', 'second.mpd', 'third.mpd'])
+    example.load(url)
+  assert.equal(example.art.dash, example.engines[2])
+  assert.equal(example.art.dash.video, example.video)
+  assert.equal(example.art.dash.autoplay, false)
+  assert.deepEqual(example.engines.map(engine => engine.destroyed), [1, 1, 0])
+  const hooks = example.hooks.filter(hook => hook.event === 'destroy')
+  assert.equal(hooks.length, 1)
+  for (const hook of hooks) {
+    hook.callback()
+    hook.callback()
+  }
+  assert.deepEqual(example.engines.map(engine => engine.destroyed), [1, 1, 1])
+})
+
+test('unsupported DASH creates no SDK or SDK-dependent control plugin', () => {
+  const example = loadExample(false)
+  example.load('unsupported.mpd')
+  assert.equal(example.art.notice.show, 'Unsupported playback format: mpd')
+  assert.equal(example.engines.length, 0)
+  assert.equal(example.art.option.plugins.length, 0)
+  assert.equal(example.pluginOptions.length, 0)
+  for (const hook of example.hooks.filter(hook => hook.event === 'destroy'))
+    hook.callback()
+})
+
+test('DASH audio formatter handles actual SDK nullable metadata and preserves language labels', () => {
+  const format = loadExample(true).pluginOptions[0].audio.getName
+  assert.equal(format({ lang: 'en', id: 0 }), 'EN')
+  assert.equal(format({ lang: null, id: 0 }), '0')
+  assert.equal(format({ id: 'commentary' }), 'commentary')
+  assert.equal(format({ lang: null, id: null }), 'Audio')
+})