dfs.js

var graph = {
  a: ['b', 'c'],
  b: ['d', 'e', 'f'],
  c: ['g'],
  g: ['h']
};

function traverseDFS(root, target, graph, visited) {
  if (!visited) visited = {};
  if (root.toString() === target.toString()) return target;
  var graphRoot = graph[root];
  if (!graphRoot) return;

  // traverse edges of the root
  for (var edge = 0; edge < graphRoot.length; edge++) {
    var graphRootEdge = graphRoot[edge];
    var result;
    if (!visited[graphRootEdge]) {
      visited[graphRootEdge] = true;
      result = traverseDFS(graphRootEdge, target, graph, visited);
    }
    if (result) return result;
  }
  return;
}

traverseDFS('a', 'g', graph);