diff --git a/src/index.js b/src/index.js
index 1cac4a8..5deec59 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,12 +1,4 @@
-const EventSyncer = require('./eventSyncer.js')
+const EventSyncer = require('./eventSyncer.js');
+EventSyncer.operators = require('./operators');
 
-const eventSyncer = new EventSyncer(web3);
-
-eventSyncer.init(() => {});
-
-  // eventSyncer.trackEvent('contractEvent', ((x) => x.from === "0x123")).pipe(map(x => x.rating), myscan, mymap).subscribe((v) => {
-    // console.dir("current average is " + v)
-  // })
-
-
-// return Event
+module.exports = EventSyncer;
diff --git a/src/operators.js b/src/operators.js
new file mode 100644
index 0000000..eacd559
--- /dev/null
+++ b/src/operators.js
@@ -0,0 +1,44 @@
+const { of, pipe }  = require('rxjs');
+const { map, pluck, reduce } = require('rxjs/operators');
+
+function $takeProps() {
+  const args = Object.values(arguments);
+  return pipe(
+    map(v => {
+      const r = {};
+      args.forEach(a => {
+        r[a] = v[a];
+      });
+      return r;
+    }),
+  );
+}
+
+/*
+// ex 1
+of({a: 1, b:2, e: 1}, {a: 0, c: 1, b:3}, {a: 0, d: 1, b:1})
+  .pipe($takeProps("a", "b", "e"))
+  .subscribe((v) => console.log(v));
+*/
+
+function $average() {
+  return pipe(
+    reduce((accum, curr) => ({
+      sum: accum.sum + curr,
+      count: accum.count + 1
+    }), { sum: 0, count: 0 }),
+    map(o => o.sum / o.count)
+  );
+}
+
+/*
+of(10, 3, 4)
+  .pipe($average())
+  .subscribe((v) => console.log(v));
+*/
+
+
+module.exports = {
+    $takeProps,
+    $average
+};
\ No newline at end of file
diff --git a/webpack.common.js b/webpack.common.js
index 0b5f294..74f743a 100644
--- a/webpack.common.js
+++ b/webpack.common.js
@@ -2,7 +2,7 @@ const path = require('path');
 
 const webConfig = {
   target: 'web',
-  entry: path.join(__dirname, "src/eventSyncer.js"),
+  entry: path.join(__dirname, "src/index.js"),
   output: {
     path: path.resolve(__dirname, "dist"),
     filename: 'browser.js',