Below are my codes:
 

Component:

<aura:component controller="createRecord">
    <aura:attribute name="Campitem" type="Camp_Item__c" default="{'sobjectType': 'Camp_item__C',
                                               'Name'          : '',
                                               
                                               'Description__c': ''
                              }" />
    <lightning:input label="Name" type="Text" name="Name" value="{!v.Campitem.Name}" />
    
    <lightning:input label="Description" type="text" name="desc" value="{!v.Campitem.Description__c}" />
    <lightning:button label="Create" onclick="{!c.createRec}"/> 
</aura:component>

 

Controller:

({
    
	createRec : function(component, event, helper) {
		
        //getting the candidate information
        var camp = component.get("v.Campitem");
        
             //Validation
        if($A.util.isEmpty(camp.Name) || $A.util.isUndefined(camp.Name)){
            alert('Name is Required');
            return;
        }            
        if($A.util.isEmpty(camp.Description__c) || $A.util.isUndefined(camp.Description__c)){
            alert('Desc is Required');
            return;
        }
        
        //Calling the Apex Function
        var action = component.get("c.createCampRec");
        console.log(camp);
        //Setting the Apex Parameter
        action.setParams({
            cp : camp
        });
       
       

        //Setting the Callback
        action.setCallback(this,function(a){
            //get the response state
            var state = a.getState();
            
            //check if result is successfull
            if(state == "SUCCESS"){
                //Reset Form
               var ncamp = {'sobjectType': 'Camp_item__C',
                                               'Name'          : '',                                             
                                               'Description__c': ''
                                               
                              }
                component.set({"v.Campitem": ncamp });
                alert('Record is Created Successfully');
            } else if(state == "ERROR"){
                alert('Error in calling server side action');
            }
        });
        
		//adds the server-side action to the queue      
  $A.enqueueAction(action);  
       
	}
})

 

Apex class:

public with sharing class createRecord {
 
    @AuraEnabled
    public static void createCampRec(Camp_item__c cp )
        
    {
        try{
            System.debug('Check '+cp);
            
            if(cp != null){
                insert cp;
            }
            
        } catch (Exception ex){
            
        }
        
 }
}

When I click on create , The record is getting inserted, but I am getting error as below:

This page has an error. You might just need to refresh it.
Error in $A.getCallback() [key.indexOf is not a function]
Callback failed: apex://createRecord/ACTION$createCampRec
Failing descriptor: {c:Camp1}

Please help