How to update the only modified records in aura:iteration using index

Question

Is there any way to update only modified records in the list that is iterated through aura:iteration. I am trying to get index at row level using event.currentTarget. But event.currentTarget is returning undefined. Is there any solution for this kind of scenario?

Below is my code pattern

Component

 <table class="slds-table slds-table_bordered slds-table_cell-buffer week-table">
    <aura:iteration items="{!v.roleWrappersByBR}" var="item" indexVar="index">
         <tr class="hoursHover"> 
               <td class="roles">
                        {!item.DS_Role} &nbsp; {!item.Duplicate_Role}
               </td>

               <aura:iteration items="{!v.weekJunctionWrappersByBR}" var="week1" indexVar="index2">
               <td class="hours2" style="{!'background:' + week1.color+';padding:4px'}" data-value="{!index2}" data-row-index="{!index2}">
                     <ui:inputText class="hoursInput" value="{!week1.Hours}" label="{!index2}" updateOn="change" change="{!c.checkWeeksInput}"/>
               </td>
               </aura:iteration>
         </tr>
     </aura:iteration> 
</table>  
        <ui:button label="Save Hours" press="{!c.SaveWeeks}" 
                   class="slds-button" disabled="{!v.isReadOnly}"/>

Controller

checkWeeksInput : function(component,event,helper){

    console.log('check values ',event.currentTarget,' -- ',event.getSource().get("v.value") );

}

Answer 1

To get the index from your current code, you can use the following code:

var index = event.target.closest('[data-row-index]').dataset.rowIndex;

Please be aware that this is not IE 11 compatible. If you want an IE 11 compatible solution, move your handler up to the table cell:

<td ... data-value="{!index2}" data-row-index="{!index2}" onchange="{!c.checkWeeksInput}">

(or, alternatively, use a span or div wrapper around the input element; you can catch handlers, there, too)

This simplifies your code to just:

var index = event.target.dataset.rowIndex;