Handling actions with controllers

1.campingListItem.cmp
<aura:component >
    <aura:attribute name="item" type="Camping_Item__c" required="true"/>
    
    //refer object fields API for each fields given
    <p>Name : <ui:outputText value="{!v.item.Name}"/></p>
    
    <p>Price:
    <lightning:formattedNumber value="{!v.item.Price__c}" style="currency"/>
    </p>
    
    
    <p>Quantity:
    <lightning:formattedNumber value="{!v.item.Quantity__c}" style="number"/>
    </p>
    
    
    <p>
    <lightning:input type="toggle"                            
                         label="Packed?"                           
                         name="packed"                         
                         checked="{!v.item.Packed__c}" />
    </p>
    <p>
    <lightning:button label="Packed!"
                      onClick="{!c.packItem}"/>
    </p>
    
</aura:component>

2.campingListItemController.js

({
	packItem: function(component, event, helper) {
        var a = component.get("v.item",true);
        a.Packed__c = true;
        component.set("v.item",a);
        var btnClicked = event.getSource();
        btnClicked.set("v.disabled",true);
    }
})