support filter callbacks

src/eventSyncer.js

@@ -49,11 +49,19 @@ class EventSyncer {
   }
 
   // trackEvent(eventName, filterConditions) {
-  trackEvent(contractInstance, eventName, filterConditions) {
+  trackEvent(contractInstance, eventName, filterConditionsOrCb) {
     // let eventKey = eventName + "-from0x123";
     let eventKey = eventName;
     let namespace = randomString()
 
+
+    let filterConditions, filterConditionsCb;
+    if (typeof filterConditionsOrCb === 'function') {
+      filterConditionsCb = filterConditionsOrCb
+    } else {
+      filterConditions = filterConditionsOrCb
+    }
+
     let tracked = this.db.getCollection('tracked')
     let lastEvent = tracked.find({ "eventName": eventName })[0]
     if (!lastEvent || lastEvent.length <= 0) {
@@ -93,6 +101,10 @@ class EventSyncer {
             return;
           }
         }
+      } else if (filterConditionsCb) {
+        if (!filterConditionsCb(event.returnValues)) {
+          return;
+        }
       }
 
       this.events.emit("event-" + eventName + "-" + namespace, event);

test/test1.js

@@ -96,9 +96,11 @@ async function run() {
 
     // TODO: would be nice if trackEvent was smart enough to understand the type of returnValues and do the needed conversions
     // eventSyncer.trackEvent(RatingContract, 'Rating', ((x) => true)).pipe(map(x => parseInt(x.rating)), myscan, mymap).subscribe((v) => {
+
+    // eventSyncer.trackEvent(RatingContract, 'Rating').pipe(map(x => parseInt(x.rating)), myscan, mymap).subscribe((v) => {
     // eventSyncer.trackEvent(RatingContract, 'Rating', ((x) => true)).pipe(map(x => x.rating)).subscribe((v) => {
 
-    eventSyncer.trackEvent(RatingContract, 'Rating').pipe(map(x => parseInt(x.rating)), myscan, mymap).subscribe((v) => {
+    eventSyncer.trackEvent(RatingContract, 'Rating', ((x) => true)).pipe(map(x => parseInt(x.rating)), myscan, mymap).subscribe((v) => {
       console.dir("value is ")
       console.dir(v)
     });