refactor(core): CORE-09 isolate source operations and settle cancelled switches

packages/artplayer/src/player/switchMix.ts

@@ -0,0 +1,10 @@
+import type { SwitchHost, SwitchMethods } from '../source/types'
+import { switchSource } from '../source/switch'
+import { def } from '../utils'
+
+export default function switchMix(art: SwitchHost): asserts art is SwitchHost & SwitchMethods {
+  const switchUrl = (url: string) => switchSource(art, url, 0)
+  def(art, 'switchQuality', { value: (url: string) => switchSource(art, url, art.currentTime) })
+  def(art, 'switchUrl', { value: switchUrl })
+  def(art, 'switch', { set: switchUrl })
+}