This shows how to work through navigation and encode the Topic Search String

TopicNavigationHelper.js

if (component.isValid() && state === "SUCCESS") {
				for (i = 0; i < response.getReturnValue().length; i++) {
					var topic = {};
        			topic = { 'sobjectType': 'Topic','Name': '' ,'Id' :'','Label' :''};
        			topic.Name = encodeURIComponent(response.getReturnValue()[i].Name);
        			topic.Label = response.getReturnValue()[i].Name;
        			topic.Id = response.getReturnValue()[i].Id;
        			topicslst.push(topic);
			    }
			    console.log('TOPICS..'+topicslst);
				component.set("v.lsttopics", topicslst);
			}