Topological sorting

Topological sorting

var Graph = function() {
  
  var nodes = {
    'a': { id: 'a', state: 'unvisited', output: ['b','c','d']},
    'b': { id: 'b', state: 'unvisited', output: ['e']},
    'c': { id: 'c', state: 'unvisited', output: ['e']},
    'd': { id: 'd', state: 'unvisited', output: ['f']},
    'e': { id: 'e', state: 'unvisited', output: ['f']},
    'f': { id: 'f', state: 'unvisited', output: ['g']},
    'g': { id: 'g', state: 'unvisited', output: []}
  };
  
  var nodes = {
    'a': { id: 'a', state: 'unvisited', output: ['b','c']},
    'b': { id: 'b', state: 'unvisited', output: ['c']},
    'c': { id: 'c', state: 'unvisited', output: []},
  };
  
  
  this.getNodeById = function(name) {
     var result = nodes[name];
     if (result) { return result } else
       throw new Error('Node not found');
  }
  
  this.getAllNodes = function() {
    var result = [];
    for (var node in nodes) {
      result.push(node);
    }
    return result;  
  }
}

function topologicalSort(graph) {
    var solution = [];
    for (var j = 0; j < graph.getAllNodes().length; j++) {
        if (graph.getNodeById(graph.getAllNodes()[j]).state === 'unvisited') {
            var startNode = graph.getNodeById(graph.getAllNodes()[j]);
            var stack = [startNode];
            while (stack.length > 0) {
                var node = stack[stack.length - 1];
                if (node.state === 'extracted') {
                    solution.push(stack.pop().id);
                } else {
                    for (var i = 0; i < node.output.length; i++) {
                        var dest = graph.getNodeById(node.output[i]);
                        if (stack.indexOf(dest) > -1) {
                            throw new Error('Loop found');
                        } else
                        if (dest.state === 'unvisited') {
                            dest.state = 'visited';
                            stack.push(dest);
                        }
                    }
                    node.state = 'extracted';
                }
            }
        }
    }
    return solution.reverse();
}

function regularDFS(graph, startNode) {
  var solution = [];
  var stack = [startNode];
  while (stack.length > 0) {
    var node = stack.pop();
    solution.push(node.id);
    node.state = 'visited';
    for (var i=0; i < node.output.length; i++) {
      var dest = graph.getNodeById(node.output[i]);
      if (dest.state === 'unvisited') {
        stack.push(dest);
      }
    }
  }
  return solution;
}

console.log('topological sort: ', topologicalSort(new Graph(),new Graph().getNodeById('a')));
console.log('regular dfs: ', regularDFS(new Graph(),new Graph().getNodeById('a')));