Code to Show LockerService In action

searchApp

<aura:application extends="force:slds">
    <c:searchCmp />
</aura:application>

searchCmp.cmp

<aura:component implements="force:appHostable,flexipage:availableForAllPageTypes" access="global" >
	<aura:attribute name="searchTerm" type="String" />
        <lightning:layout multipleRows="true" horizontalAlign="center" verticalAlign="center">
            <lightning:layoutItem flexibility="auto" size="6">
              <lightning:input type="search" aura:id="searchBox" label="Search" name="search" placeholder="Enter Search Term"/>
            </lightning:layoutItem>
            <lightning:layoutItem flexibility="auto" size="4" padding="horizontal-small">
                 <lightning:button variant="brand" label="Search" title="" onclick="{! c.handleClick }" />
            </lightning:layoutItem>
            <lightning:layoutItem flexibility="auto" padding="around-large" size="6">
              <p> You searched for {!v.searchTerm}</p>
            </lightning:layoutItem>
        </lightning:layout>
</aura:component>
   

searchCmpController.js

({
  handleClick : function(component, event, helper) {
    helper.setSearchTerm(component, event);
  }
})

searchCmpHelper.js

({
  setSearchTerm : function(component, event) {
        var searchTerm = component.find('searchBox').getElement().value;
        console.log(searchTerm);
        component.set("v.searchTerm",searchTerm);
  }
})