ramda-tree-view.js

var a = {
  selectedPath: [],
  nodes: [{
    title: 'core',
    path:['nodes',0],
    selected: false,
    tabIndex: -1
  },
         {
    title: 'core',
    path:['nodes',1],
    selected: false,
           tabIndex: -1
  }
         ]
}



const selectedPath = ['nodes',0];
const selectedLens = lensPath(selectedPath);
//hasSelectedPath:: object -> bollean
const hasSelectedPath = compose(not,isEmpty, prop('selectedPath') )
console.log(hasSelectedPath(a)); 
//updateNode :: Object -> f Object
const toggleNode = evolve({
  selected: not,
  tabIndex: add(-1)
});
const toggleSelectedPath = over(selectedLens, toggleNode); 
toggleSelectedPath(a);