add isSafari in instance

packages/artplayer/src/index.js

@@ -37,9 +37,7 @@ export default class Artplayer extends Emitter {
 
         this.isFocus = false;
         this.isDestroy = false;
-        this.userAgent = utils.userAgent;
-        this.isMobile = utils.isMobile;
-        this.isWechat = utils.isWechat;
+
         this.whitelist = new Whitelist(this);
         this.template = new Template(this);
         this.events = new Events(this);
@@ -175,6 +173,22 @@ export default class Artplayer extends Emitter {
         };
     }
 
+    get userAgent() {
+        return utils.userAgent;
+    }
+
+    get isMobile() {
+        return utils.isMobile;
+    }
+
+    get isWechat() {
+        return utils.isWechat;
+    }
+
+    get isSafari() {
+        return utils.isSafari;
+    }
+
     get proxy() {
         return this.events.proxy;
     }