const util = require('util');

var structure = {
  root: {
    path: '/main1',
    nodes: {
      node1: {
        path: 'node1',
      },
      node2: {
        path: 'node2',
        nodes: {
          subnode1: {
            path: 'subnode1',
          },
          subnode2: {
            path: 'subnode2',
          },
          subnode3: {
            path: 'subnode3',
          },
        },
      },
      node3: {
        path: 'node3',
      },
    },
  },
};

var setName = (element) => {
  if (element.nodes != undefined) {
    Object.keys(element.nodes).forEach(node => {
      const nodeElem = element.nodes[node];
      nodeElem.name = (element.name || element.path )+ "/" + nodeElem.path;

      setName(element.nodes[node])
    });
  }
};

setName(structure.root);

console.log(util.inspect(structure, { depth: 100 }));