FIX: change build script to enable standalone

dist/mempool.js

@@ -653,16 +653,19 @@ Object.defineProperty(exports, "__esModule", { value: true });
 var browserWS = function (options, defaultWs, websocketEndpoint) {
     var ws = new WebSocket(websocketEndpoint || defaultWs);
     ws.addEventListener('open', function open() {
-        ws.send(JSON.stringify({ action: 'init' }));
-        setInterval(function timeout() {
-            ws.send(JSON.stringify({
-                action: 'want',
-                data: options,
-            }));
-        }, 500);
+        handleMessage(ws, options);
     });
     return ws;
 };
+var handleMessage = function (ws, options) {
+    ws.send(JSON.stringify({ action: 'init' }));
+    setInterval(function timeout() {
+        ws.send(JSON.stringify({
+            action: 'want',
+            data: options,
+        }));
+    }, 500);
+};
 exports.default = browserWS;
 
 },{}],10:[function(require,module,exports){