graph.js

var Graph = function(){
  this.nodes = [];
}

Graph.prototype.addNode = function(val){
  var exists = false;
  this.nodes.forEach(function(el){
    if(el[0] === val){
      exists = true;
    }
  });
  if(!exists){
    this.nodes.push([val,[]]);
  }
  return !exists;
}


Graph.prototype.removeNode = function(val){
  var j;
  var k;
  if(this.getNode(val)){
    this.nodes.forEach(function(el, i){
      if(el[0] === val){
        j = i;
      } else {
        el[1].forEach(function(edge, ind){
          if(edge[0] === val){
            k = ind;
          }
        });
        el[1].splice(k,1);
      }
    });
    this.nodes.splice(j,1);
  }
}

Graph.prototype.addEdge = function(node1, node2, w, directed){
  if(this.getNode(node1) && this.getNode(node2)){
    var edges1 = this.getEdges(node1);
    var edges2 = this.getEdges(node2);
    var found = false;
    directed = directed || false;
    w = w || 1;
    this.nodes.forEach(function(el,i){
      if(el[0] === node1){
        edges1.forEach(function(edge,j){
          if(edge[0] === node2){
            this.nodes[i][1][j] = [node2, w];
            found = true;
          }
        },this)
        if(!found){
          el[1].push([node2, w]);
        }
      }
    },this);
    if(!directed){
      this.addEdge(node2,node1,w, true);
    }
  }
}

Graph.prototype.removeEdge = function(node1, node2){
  if(this.getNode(node1) && this.getNode(node2)){
    this.nodes.forEach(function(el){
      if(el[0] === node1){
        el[1].forEach(function(edge, i){
          if(edge[0] === node2){
            el[1].splice(i,1);
          }
        });
      }
    });
  }
}

Graph.prototype.getEdges = function(node){
  var res = null;
  this.nodes.forEach(function(el){
    if(el[0] === node){
      res = el[1];
    }
  });
  return res;
}

Graph.prototype.getNode = function(val){
  var res = null;
  this.nodes.forEach(function(el){
    if(el[0] === val){
      res = el;
    }
  });
  return res;
}



//[val,[[edge, w]...]]