old_contents: import Ember from 'ember';
  import ENV from 'plenario-explorer/config/environment';
  
  export default Ember.Controller.extend({
    modelArrived: Ember.observer('model', function() {
      const nodeList = this.get('model.nodes');
      const nodeTuples = nodeList.map(node => {
        return [node.properties.id, node.properties];
      });
      const nodeMap = new Map(nodeTuples);
      this.set('nodeMap', nodeMap);
      // TODO: Move magic node id to environment config
      this.set('selectedNode', nodeMap.get(ENV.defaultNode));
    }),
  
    actions: {
      onSelect(nodeId) {
        const newNode = this.get('nodeMap').get(nodeId);
        this.set('selectedNode', newNode);
      }
    }
  });
  
new_contents: import Ember from 'ember';
  // import ENV from 'plenario-explorer/config/environment';
  
  export default Ember.Controller.extend({
    modelArrived: Ember.observer('model', function() {
      const nodeList = this.get('model.nodes');
      const nodeTuples = nodeList.map(node => {
        return [node.properties.id, node.properties];
      });
      const nodeMap = new Map(nodeTuples);
      this.set('nodeMap', nodeMap);
      this.set('selectedNode', nodeList[0].properties);
    }),
  
    actions: {
      onSelect(nodeId) {
        const newNode = this.get('nodeMap').get(nodeId);
        this.set('selectedNode', newNode);
      }
    }
  });
  
subject: Set default node as first returned from API