BidViewability: Refactored the init function (#13141)

* Refactored the init function

* Added new line for linting error

* removed the listener before firing the handler

* Removed event listener when module is disabled

---------

Co-authored-by: pm-azhar-mulla <[email protected]>

Author: pm-azhar-mulla

modules/bidViewability.js

@@ -58,7 +58,8 @@ export let logWinningBidNotFound = (slot) => {
   logWarn(`bid details could not be found for ${slot.getSlotElementId()}, probable reasons: a non-prebid bid is served OR check the prebid.AdUnit.code to GPT.AdSlot relation.`);
 };
 
-export let impressionViewableHandler = (globalModuleConfig, slot, event) => {
+export let impressionViewableHandler = (globalModuleConfig, event) => {
+  const slot = event.slot;
   let respectiveBid = getMatchingWinningBidForGPTSlot(globalModuleConfig, slot);
 
   if (respectiveBid === null) {
@@ -78,24 +79,28 @@ export let impressionViewableHandler = (globalModuleConfig, slot, event) => {
   }
 };
 
-export let init = () => {
-  events.on(EVENTS.AUCTION_INIT, () => {
-    // read the config for the module
-    const globalModuleConfig = config.getConfig(MODULE_NAME) || {};
-    // do nothing if module-config.enabled is not set to true
-    // this way we are adding a way for bidders to know (using pbjs.getConfig('bidViewability').enabled === true) whether this module is added in build and is enabled
-    if (globalModuleConfig[CONFIG_ENABLED] !== true) {
-      return;
-    }
-    // add the GPT event listener
-    window.googletag = window.googletag || {};
-    window.googletag.cmd = window.googletag.cmd || [];
+const handleSetConfig = (config) => {
+  const globalModuleConfig = config || {};
+  window.googletag = window.googletag || {};
+  window.googletag.cmd = window.googletag.cmd || [];
+
+  // do nothing if module-config.enabled is not set to true
+  // this way we are adding a way for bidders to know (using pbjs.getConfig('bidViewability').enabled === true) whether this module is added in build and is enabled
+  const impressionViewableHandlerWrapper = (event) => {
+    window.googletag.pubads().removeEventListener(GPT_IMPRESSION_VIEWABLE_EVENT, impressionViewableHandlerWrapper);
+    impressionViewableHandler(globalModuleConfig, event);
+  };
+
+  if (globalModuleConfig[CONFIG_ENABLED] !== true) {
     window.googletag.cmd.push(() => {
-      window.googletag.pubads().addEventListener(GPT_IMPRESSION_VIEWABLE_EVENT, function(event) {
-        impressionViewableHandler(globalModuleConfig, event.slot, event);
-      });
+      window.googletag.pubads().removeEventListener(GPT_IMPRESSION_VIEWABLE_EVENT, impressionViewableHandlerWrapper);
     });
+    return;
+  }
+  // add the GPT event listener
+  window.googletag.cmd.push(() => {
+    window.googletag.pubads().addEventListener(GPT_IMPRESSION_VIEWABLE_EVENT, impressionViewableHandlerWrapper);
   });
 }
 
-init()
+config.getConfig(MODULE_NAME, config => handleSetConfig(config[MODULE_NAME]));

test/spec/modules/bidViewability_spec.js

@@ -19,6 +19,10 @@ const GPT_SLOT = {
   }
 };
 
+const EVENT_OBJ = {
+  slot: GPT_SLOT
+}
+
 const PBJS_WINNING_BID = {
   'adUnitCode': '/harshad/Jan/2021/',
   'bidderCode': 'pubmatic',
@@ -282,7 +286,7 @@ describe('#bidViewability', function() {
         firePixels: true
       };
       winningBidsArray.push(PBJS_WINNING_BID);
-      bidViewability.impressionViewableHandler(moduleConfig, GPT_SLOT, null);
+      bidViewability.impressionViewableHandler(moduleConfig, EVENT_OBJ);
       // fire pixels should be called
       PBJS_WINNING_BID.vurls.forEach((url, i) => {
         let call = triggerPixelSpy.getCall(i);
@@ -314,7 +318,7 @@ describe('#bidViewability', function() {
         deferBilling: true
       }
       winningBidsArray.push(bid);
-      bidViewability.impressionViewableHandler(moduleConfig, GPT_SLOT, null);
+      bidViewability.impressionViewableHandler(moduleConfig, EVENT_OBJ);
       expect(triggerBillingSpy.callCount).to.equal(1);
       sinon.assert.calledWith(triggerBillingSpy, bid);
     });