Aura.Action : Lightning Framework Specific Attributes Type

SK_AuraActionChildCmp.cmp

<aura:component >
    <aura:attribute name="ltngMessage" type="string"/>
    <aura:attribute name="closeChildDivFunction" type="Aura.Action" default="{!c.defaultCloseAction}"/>
    <div aura:id="maincontainer" style="background-color:#E6E6FA;border-style: solid;height:100px;margin:2%;padding:1%;">
        <b>This is Child component inside SK_AuraActionDemoCmp</b>
        <br/>
        <lightning:button label="Close via ChildCmp JS function" variant="neutral"  onclick="{!c.defaultCloseAction}"/>
        
        <lightning:button label="Close via Parent JS function" variant="brand"  onclick="{!v.closeChildDivFunction}"/>
        
    </div>
</aura:component>

SK_AuraActionChildCmpController.js

({
	defaultCloseAction : function(component, event, helper) {
        //perform you logic and close the modal dialog
        component.set("v.ltngMessage","Close via ChildCmp JS function button clicked.Please refresh your browser if you again want to load this demo component");
        var mc=component.find("maincontainer");
        $A.util.addClass(mc, "slds-hide");
    } 
})

SK_AuraActionDemoApp.app

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

SK_AuraActionDemoCmp.cmp

<aura:component >
    <aura:attribute name="ltnguserActionMessage" type="string" default="Waiting for User Action"/>
    <div style="background-color:#e7eff8;border-style: solid;padding:2%;">
        <b> This is Parent(SK_AuraActionDemoCmp) component </b>
        <br/>
        ltnguserActionMessage value-<b>{!v.ltnguserActionMessage}</b>
        <br/>
        
    <div aura:id="childContainer" >
        <p>This content is inside childContainer div</p>
        <ul class="slds-list--ordered">
        	<li>If user clicks on "Close via Parent JS function" button,then this content will also get removed</li>
        	<li>If user clicks on "Close via ChildCmp JS function" button,then only child component body will be removed</li>
        </ul>
        <c:SK_AuraActionChildCmp
                             ltngMessage="{!v.ltnguserActionMessage}" 
                             closeChildDivFunction="{!c.destroyChildCmp}"/>
    </div>
        </div>
   
</aura:component>

SK_AuraActionDemoCmpController.js

({
	destroyChildCmp: function(component) {
        component.set("v.ltnguserActionMessage","Close via Parent JS function button clicked. Please refresh your browser if you again want to load this demo component.");
        var cmp = component.find('childContainer');
        cmp.set("v.body",[]);
    }
})