refactor(core): CORE-08 type plugin registration and guard closed instances

test/types/plugins-public.ts

@@ -0,0 +1,29 @@
+import type { PluginFactory, Plugins } from 'artplayer'
+import Artplayer from 'artplayer'
+
+declare module 'artplayer/types' {
+  interface Plugins {
+    typedExtension?: { update: (count: number) => void }
+  }
+  interface Events {
+    'typed-extension:update': [count: number]
+  }
+}
+
+const factory: PluginFactory = function (art) {
+  const receiver: number = this.id
+  return { name: 'typedExtension', update(count: number) {
+    art.emit('typed-extension:update', count + receiver)
+  } }
+}
+const art = new Artplayer({ container: '#player', plugins: [factory] }, function (instance) {
+  this.plugins.typedExtension?.update(1)
+  instance.plugins.typedExtension?.update(2)
+})
+const plugins: Plugins = art.plugins
+plugins.typedExtension?.update(3)
+art.on('typed-extension:update', count => count.toFixed())
+// @ts-expect-error Installed result methods retain their argument types.
+plugins.typedExtension?.update('bad')
+// @ts-expect-error Declared event listener payloads remain checked.
+art.on('typed-extension:update', (count: string) => count)