Hello everyone, I'm stuck at the last component challenge Aura,

I managed the challenge but when I try to insert a form in the database it makes me mistakes.

I tested with two submitform function
CampingListFormController.js

({
    submitForm: function(component, event, helper) {    
        if(helper.validateItemForm(component)){
            // Create the new item
            var newItem = component.get("v.newItem");
            helper.addItem(component, newItem);
        }
        
    },
    
    submitFormm: function(component, event, helper) {
        var validExpense = component.find('campingform').reduce(function (validSoFar, inputCmp) {
            // Displays error messages for invalid fields
            inputCmp.showHelpMessageIfInvalid();
            return validSoFar && inputCmp.get('v.validity').valid;
        }, true);
        // If we pass error checking, do some real work
        if(validExpense){
            // Create the new expense
            var newItem = component.get("v.newItem");
            helper.addItem(component, newItem);
        }
    }
    
})

for the first function SubmitForm (with only one "m" at the end) i have as error :
Action failed: c:campingListForm$controller$submitForm [Cannot read property 'get' of undefined] Failing descriptor: {c:campingListForm$controller$submitForm}

for the second function SubmitFormm (with two"m" at the end) i have as error :
Action failed: c:campingListForm$controller$submitFormm [component.getItem is not a function] Failing descriptor: {c:campingListForm$controller$submitFormm}

There is my campingListFormHelper.js

({
 addItem: function(component, newItem) {
    var addItem = component.getItem("addItem");
    addItem.setParams({ "item": item });
    addItem.fire();
            component.set("v.newItem",{ 'sobjectType': 'Camping_Item__c',
                    'Name': '',
                    'Quantity__c': 0,
                    'Price__c': 0,
                    'Packed__c': false });
},
    

		validateItemForm: function(component) {
		
              // Simplistic error checking
        var validItem = true;

        // Name must not be blank
        var nameField = component.find("itemname");
        var itemname = nameField.get("v.value");
        if ($A.util.isEmpty(itemname)){
            validItem = false;
            nameField.set("v.errors", [{message:"Item name can't be blank."}]);
        }
        else {
            nameField.set("v.errors", null);
        }
        
        // Quantity must not be blank
        var quantityField = component.find("quantity");
        var quantity = nameField.get("v.value");
        if ($A.util.isEmpty(quantity)){
            validItem = false;
            quantityField.set("v.errors", [{message:"Quantity can't be blank."}]);
        }
        else {
            quantityField.set("v.errors", null);
        }
		// Price must not be blank
        var priceField = component.find("price");
        var price = priceField.get("v.value");
        if ($A.util.isEmpty(price)){
            validItem = false;
            priceField.set("v.errors", [{message:"Price can't be blank."}]);
        }
        else {
            quantityField.set("v.errors", null);
        }
            return (validItem);

	}
})