FunCommunityComponent.cmp

<aura:component implements="forceCommunity:availableForAllPageTypes" controller="FuncommunityController">
    <aura:attribute name="topic" type="String" />
    <aura:handler name="init" value="{!this}" action="{!c.getTopicName}" />
    <div>
      <h1>TOPIC FROM SERVER {!v.topic}</h1>
    </div>
</aura:component>