graph.js

;(function (ns) {

  var gid = (function (i) {
    return function () {
      return i++;
    }
  })(0);

  function Node(graph, val) {
    this.gid = gid();
    this.graph = graph;
    this.val = val;
    this.inputs = [];
    this.outputs = [];
  }

  function deleteItem(arr, i) {
    return arr.slice(0, i).concat(arr.slice(i + 1));
  }

  Node.prototype.resolveNode = function (node, fn) {
    return fn.call(this, this.graph.getNode(node));
  };

  Node.nodeMethod = function (fn) {
    return function (node) {
      return this.resolveNode(node, function (node) {
        return fn.call(this, node);
      });
    };
  };

  Node.prototype.addLinkTo = Node.prototype.linkTo =
      Node.nodeMethod(function (node) {
        node.inputs.push(this);
        this.outputs.push(node);
        return node;
      });
  Node.prototype.addLinkFrom = Node.prototype.linkFrom =
      function (node) {
        return node.addLinkTo(this);
      };
  Node.prototype.existsLinkTo = Node.nodeMethod(function (node) {
    return this.outputs.indexOf(node) >= 0;
  });
  Node.prototype.existsLinkFrom = function (node) {
    return node.existsLinkTo(this);
  };
  Node.prototype.removeLinkTo = Node.nodeMethod(function (node) {
    var i = this.output.indexOf(node);
    var j = node.input.indexOf(this);
    if (i >= 0 && j >= 0) {
      this.outputs = deleteItem(this.outputs, i);
      this.inputs = deleteItem(this.inputs, j);
    }
    return this;
  });
  Node.prototype.removeLinkFrom = function (node) {
    return node.removeLinkTo(this);
  };
  Node.prototype.removeAllLinks = Node.prototype.isolate =
      function (listName) {
        if (!listName) {
          this.removeAllLinks('inputs');
          this.removeAllLinks('outputs');
          return this;
        }
        var n2, k;
        var n2ListName = listName === 'inputs' ? 'outputs' : 'inputs';
        for (var j = 0; j < this[listName].length; j++) {
          n2 = this[listName][j];
          k = n2[n2ListName].indexOf(this);
          if (k < 0) {
            throw {
              from: "removeAllLinks",
              data: { list: n2[n2ListName], ctx: this }
            };
          }
          n2[n2ListName] = deleteItem(n2[n2ListName], k);
        }
        return this;
      };

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

  Graph.prototype.resolveNode = function (node, fn) {
    return fn.call(this, this.getNode(node));
  };

  Graph.nodeMethod = Node.nodeMethod;

  Graph.prototype.getNode = Graph.prototype.get =
      function (input) {
        return typeof input === 'object' ? input : this.nodes[this.keys[input]];
      };
  Graph.prototype.pushNode = Graph.prototype.push =
      function (node, key) {
        this.keys[key] = this.nodes.length;
        this.nodes.push(node);
        return node;
      };
  Graph.prototype.createNode = Graph.prototype.create =
      function (val, key) {
        return this.pushNode(new Node(this, val), key);
      };
  Graph.prototype.removeNode = Graph.prototype.remove =
      Graph.nodeMethod(function (node) {
        var i = this.nodes.indexOf(node);
        if (i >= 0) {
          node.removeAllLinks();
          deleteItem(this.nodes, index);
        }
        return this;
      });
  Graph.prototype.existsNode = Graph.prototype.exists =
      Graph.nodeMethod(function (node) {
        return this.nodes.indexOf(node) >= 0;
      });

  ns.Graph = Graph;

})(window)