dijkstra.js

function solve(graph, s) {
    var solutions = {};
    solutions[s] = [];
    solutions[s].dist = 0;
    
    while(true) {
      var parent = null;
      var nearest = null;
      var dist = Infinity;
      
      //for each existing solution
      for(var n in solutions) {
        if(!solutions[n])
          continue
        var ndist = solutions[n].dist;
        var adj = graph[n];
        //for each of its adjacent nodes...
        for(var a in adj) {
          //without a solution already...
          if(solutions[a])
            continue;
          //choose nearest node with lowest *total* cost
          var d = adj[a] + ndist;
          if(d < dist) {
            //reference parent
            parent = solutions[n];
            nearest = a;
            dist = d;
          }
        }
      }
      
      //no more solutions
      if(dist === Infinity) {
          break;
      }
      
      //extend parent's solution path
      solutions[nearest] = parent.concat(nearest);
      //extend parent's cost
      solutions[nearest].dist = dist;
    }
    
    return solutions;
  }
  //create graph
  var graph = {};
  
  var layout = {
    'R': ['2'],
    '2': ['3','4'],
    '3': ['4','6','13'],
    '4': ['5','8'],
    '5': ['7','11'],
    '6': ['13','15'],
    '7': ['10'],
    '8': ['11','13'],
    '9': ['14'],
    '10': [],
    '11': ['12'],
    '12': [],
    '13': ['14'],
    '14': [],
    '15': []
  }
  
  
  for(var id in layout) {
    if(!graph[id])
      graph[id] = {};
    layout[id].forEach(function(aid) {
      graph[id][aid] = 1;
      if(!graph[aid])
        graph[aid] = {};
      graph[aid][id] = 1;
    });
  }
  
  //choose start node
  var start = '10';
  //get all solutions
  var solutions = solve(graph, start);
  
  console.log("From '"+start+"' to");
  //display solutions
  for(var s in solutions) {
    if(!solutions[s]) continue;
    console.log(" -> " + s + ": [" + solutions[s].join(", ") + "]   (dist:" + solutions[s].dist + ")");
  }