Javascript dependency graph resolution

gistfile1.js

// Dependency resolution, adapted from https://gist.github.com/1232505/f16308bc14966c8d003c2686b1c258ec41303c1f
function resolve(graph) {
  var sorted  = [], // sorted list of IDs ( returned value )
      visited = {}; // hash: id of already visited node => true

  // 2. topological sort
  Object.keys(graph).forEach(function visit(name, ancestors) {
    if (!Array.isArray(ancestors)) ancestors = [];
    ancestors.push(name);
    visited[name] = true;

    graph[name].forEach(function(dep) {
        if (ancestors.indexOf(dep) >= 0)  // if already in ancestors, a closed chain exists.
            throw new Error('Circular dependency "' +  dep + '" is required by "' + name + '": ' + ancestors.join(' -> '));

        // if already exists, do nothing
        if (visited[name]) return;
        visit(dep, ancestors.slice(0)); // recursive call
    });

    sorted.push(name);
  });

  return sorted;
}

var subscribers = {
    html: ['foo'],
    value: ['options', 'html'],
    foo: ['options'],
    bar: ['options', 'html'],
    options: [],
    css: ['value'],
    elements: ['css', 'html', 'options']
};

/*
Expected:
options
foo
html
value
bar
css
elements
*/

var execution_order = resolve(subscribers);
// var execution_order = resolve(subscribers);
execution_order.forEach(function(name) {
   console.log(name); 
});