From 09ee4f277f97a8a54effeade938a721c5f846b24 Mon Sep 17 00:00:00 2001
From: Ezerous <ezerous@gmail.com>
Date: Mon, 8 Feb 2021 11:57:55 +0200
Subject: [PATCH] Fix for events firing multiple times

---
 package.json                   |  2 +-
 src/contracts/contractsSaga.js | 17 +++++++++++++++--
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/package.json b/package.json
index 1da0e22..6a8eded 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ezerous/drizzle",
-  "version": "0.4.1",
+  "version": "0.4.2",
   "description": "A reactive data-store for web3 and smart contracts.",
   "license": "MIT",
   "author": "Ezerous <ezerous@gmail.com>",
diff --git a/src/contracts/contractsSaga.js b/src/contracts/contractsSaga.js
index 12a927f..f14b16d 100644
--- a/src/contracts/contractsSaga.js
+++ b/src/contracts/contractsSaga.js
@@ -6,6 +6,18 @@ import * as TransactionsActions from '../transactions/transactionsActions'
 /*
  * Events
  */
+
+// Patch for EVENT_FIRED being called multiple times for the same event
+let eventSet = new Set();
+
+function isEventUnique(event){
+  const size = eventSet.size;
+  eventSet.add(event.event + '-' + event.transactionHash);
+  if(eventSet.size>size)
+    return true;
+  return false;
+}
+
 export function createContractEventChannel ({
   contract,
   eventName,
@@ -14,9 +26,10 @@ export function createContractEventChannel ({
   const name = contract.contractName
 
   return eventChannel(emit => {
-    const eventListener = contract.events[eventName](eventOptions)
+    const eventListener = contract.events[eventName]()
       .on('data', event => {
-        emit({ type: ContractActions.CONTRACT_EVENT_FIRED, name, event })
+        if(isEventUnique(event))
+          emit({ type: ContractActions.CONTRACT_EVENT_FIRED, name, event })
       })
       .on('changed', event => {
         emit({ type: ContractActions.CONTRACT_EVENT_CHANGED, name, event })