Salesforce Lightning Locker test component

myLockerTest.cmp

<aura:component implements="clients:availableForMailAppAppPage,clients:hasItemContext,flexipage:availableForAllPageTypes">
    <aura:attribute name="window" type="String" access="private" />
    <aura:attribute name="document" type="String" access="private" />
	<aura:handler name="init" value="{! this }" action="{! c.init }" />
    <aura:handler Name="change" value="{!v.messageBody}" action="{!c.handleMessageBodyChanged}" />
    <!-- This has JQUERY included
        <ltng:require scripts="https://code.jquery.com/jquery-3.2.0.min.js"/>
        <br/> -->
    <lightning:card title="Custom component show body">
        <p class="slds-p-horizontal--small">
            <div id="myDiv" aura:id="div1">
            <p>See how LockerService uses secure wrappers</p>
            <p>window={!v.window}</p>
                        <p>document={!v.document}</p>
        </div>
        <lightning:button name="myButton" label="Peek in DOM"
                          aura:id="button1" onclick="{!c.peekInDom}"/>
        </p>
    </lightning:card>
</aura:component>

myLockerTestController.js

({
    init: function (cmp, event, helper) {
        cmp.set('v.window', window + '');
        cmp.set('v.document', document + '');
    },
	handleMessageBodyChanged : function(component, event, helper) {
        component.set('v.myMessageBody', event.getParam('value').trim());
	},
    peekInDom : function(cmp, event, helper) {
        console.log("div1: ", cmp.find("div1").getElement());
        
        console.log("button1: ", cmp.find("button1"));
        console.log("button name: ", event.getSource().get("v.name"));
        // add debugger statement for inspection
        // always remove this from production code
        debugger;
    }
})