To set the value of an attribute inherited from an interface, redefine the attribute in the component and set its default value. Let’s look at an example with the c:myIntf interface.
<!--c:myIntf--> <aura:interface> <aura:attribute name="myBoolean" type="Boolean" default="true" /> </aura:interface>
This component implements the interface and sets myBoolean to false.
<!--c:myIntfImpl--> <aura:component implements="c:myIntf"> <aura:attribute name="myBoolean" type="Boolean" default="false" /> <p>myBoolean: {!v.myBoolean}</p> </aura:component>