移除两个依赖

packages/artplayer/src/emitter.js

@@ -0,0 +1,42 @@
+export default class Emitter {
+    on(name, fn, ctx) {
+        const e = this.e || (this.e = {});
+        (e[name] || (e[name] = [])).push({ fn, ctx });
+        return this;
+    }
+
+    once(name, fn, ctx) {
+        const self = this;
+        function listener(...args) {
+            self.off(name, listener);
+            fn.apply(ctx, args);
+        }
+        listener._ = fn;
+        return this.on(name, listener, ctx);
+    }
+
+    emit(name, ...data) {
+        const evtArr = ((this.e || (this.e = {}))[name] || []).slice();
+        for (let i = 0; i < evtArr.length; i += 1) {
+            evtArr[i].fn.apply(evtArr[i].ctx, data);
+        }
+        return this;
+    }
+
+    off(name, callback) {
+        const e = this.e || (this.e = {});
+        const evts = e[name];
+        const liveEvents = [];
+        if (evts && callback) {
+            for (let i = 0, len = evts.length; i < len; i += 1) {
+                if (evts[i].fn !== callback && evts[i].fn._ !== callback) liveEvents.push(evts[i]);
+            }
+        }
+        if (liveEvents.length) {
+            e[name] = liveEvents;
+        } else {
+            delete e[name];
+        }
+        return this;
+    }
+}