Problem lies in this line this.targetEvt = data[0].Targets__r.Main_Target__c
. It should be this.targetEvt = i.Main_Target__c
.
Datatype of data[0].Targets__r
is an array. So, trying access the property of an array element directly from an array (without iterating thru) doesn't make sense. You are already using a for
loop where i
represents elements in the array (for Targets__r
), so you should use i.Main_Target__c
.
If you need the first element value of the child array, you can change the code to data[0].Targets__r[0].Main_Target__c
and skip the for
loop.