refactor(core): CORE-06 type media surfaces and playback hosts

packages/artplayer/src/player/durationMix.ts

@@ -0,0 +1,14 @@
+import type { MediaHost } from '../media/hosts'
+import type { MediaState } from '../media/types'
+import { def } from '../utils'
+
+export default function durationMix(art: MediaHost<Pick<MediaState, 'duration'>>): asserts art is MediaHost<Pick<MediaState, 'duration'>> & { readonly duration: number } {
+  def(art, 'duration', {
+    get: () => {
+      const { duration } = art.template.$video
+      if (duration === Infinity)
+        return 0
+      return duration || 0
+    },
+  })
+}