diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 00000000..db25765f
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,176 @@
+// Type definitions for dagre 0.7
+// Project: https://github.com/dagrejs/dagre
+// Definitions by: Qinfeng Chen <https://github.com/qinfchen>
+//                 Pete Vilter <https://github.com/vilterp>
+//                 David Newell <https://github.com/rustedgrail>
+//                 Graham Lea <https://github.com/GrahamLea>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 2.2
+
+// export as namespace dagre;
+
+declare module "dagre" {
+  export namespace graphlib {
+    class Graph<T = {}> {
+      constructor(opt?: {
+        directed?: boolean | undefined;
+        multigraph?: boolean | undefined;
+        compound?: boolean | undefined;
+      });
+
+      graph(): GraphLabel;
+      isDirected(): boolean;
+      isMultiGraph(): boolean;
+      setGraph(label: GraphLabel): Graph<T>;
+
+      edge(edgeObj: Edge): GraphEdge;
+      edge(outNodeName: string, inNodeName: string, name?: string): GraphEdge;
+      edgeCount(): number;
+      edges(): Edge[];
+      hasEdge(edgeObj: Edge): boolean;
+      hasEdge(outNodeName: string, inNodeName: string, name?: string): boolean;
+      inEdges(inNodeName: string, outNodeName?: string): Edge[] | undefined;
+      outEdges(outNodeName: string, inNodeName?: string): Edge[] | undefined;
+      removeEdge(outNodeName: string, inNodeName: string): Graph<T>;
+      setDefaultEdgeLabel(
+        callback:
+          | string
+          | ((v: string, w: string, name?: string) => string | Label)
+      ): Graph<T>;
+      setEdge(params: Edge, value?: string | { [key: string]: any }): Graph<T>;
+      setEdge(
+        sourceId: string,
+        targetId: string,
+        value?: string | Label,
+        name?: string
+      ): Graph<T>;
+
+      children(parentName: string): string | undefined;
+      hasNode(name: string): boolean;
+      neighbors(name: string): Array<Node<T>> | undefined;
+      node(id: string | Label): Node<T>;
+      nodeCount(): number;
+      nodes(): string[];
+      parent(childName: string): string | undefined;
+      predecessors(name: string): Array<Node<T>> | undefined;
+      removeNode(name: string): Graph<T>;
+      filterNodes(callback: (nodeId: string) => boolean): Graph<T>;
+      setDefaultNodeLabel(
+        callback: string | ((nodeId: string) => string | Label)
+      ): Graph<T>;
+      setNode(name: string, label: string | Label): Graph<T>;
+      setParent(childName: string, parentName: string): void;
+      sinks(): Array<Node<T>>;
+      sources(): Array<Node<T>>;
+      successors(name: string): Array<Node<T>> | undefined;
+    }
+
+    namespace json {
+      function read(graph: any): Graph;
+      function write(graph: Graph): any;
+    }
+
+    namespace alg {
+      function components(graph: Graph): string[][];
+      function dijkstra(
+        graph: Graph,
+        source: string,
+        weightFn?: WeightFn,
+        edgeFn?: EdgeFn
+      ): any;
+      function dijkstraAll(
+        graph: Graph,
+        weightFn?: WeightFn,
+        edgeFn?: EdgeFn
+      ): any;
+      function findCycles(graph: Graph): string[][];
+      function floydWarchall(
+        graph: Graph,
+        weightFn?: WeightFn,
+        edgeFn?: EdgeFn
+      ): any;
+      function isAcyclic(graph: Graph): boolean;
+      function postorder(graph: Graph, nodeNames: string | string[]): string[];
+      function preorder(graph: Graph, nodeNames: string | string[]): string[];
+      function prim<T>(graph: Graph<T>, weightFn?: WeightFn): Graph<T>;
+      function tarjam(graph: Graph): string[][];
+      function topsort(graph: Graph): string[];
+    }
+  }
+
+  export interface Label {
+    [key: string]: any;
+  }
+  export type WeightFn = (edge: Edge) => number;
+  export type EdgeFn = (outNodeName: string) => GraphEdge[];
+
+  export interface GraphLabel {
+    width?: number | undefined;
+    height?: number | undefined;
+    compound?: boolean | undefined;
+    rankdir?: string | undefined;
+    align?: string | undefined;
+    nodesep?: number | undefined;
+    edgesep?: number | undefined;
+    ranksep?: number | undefined;
+    marginx?: number | undefined;
+    marginy?: number | undefined;
+    acyclicer?: string | undefined;
+    ranker?: string | undefined;
+  }
+
+  export interface NodeConfig {
+    width?: number | undefined;
+    height?: number | undefined;
+  }
+
+  export interface EdgeConfig {
+    minlen?: number | undefined;
+    weight?: number | undefined;
+    width?: number | undefined;
+    height?: number | undefined;
+    lablepos?: "l" | "c" | "r" | undefined;
+    labeloffest?: number | undefined;
+  }
+
+  interface Constraint {
+    high: string;
+    low: string;
+  }
+
+  interface LayoutOptions {
+    constraints?: Constraint[];
+  }
+
+  export function layout(
+    graph: graphlib.Graph,
+    // layout?: GraphLabel & NodeConfig & EdgeConfig
+    options: LayoutOptions
+  ): void;
+
+  export interface Edge {
+    v: string;
+    w: string;
+    name?: string | undefined;
+  }
+
+  export interface GraphEdge {
+    points: Array<{ x: number; y: number }>;
+    [key: string]: any;
+  }
+
+  export type Node<T = {}> = T & {
+    x: number;
+    y: number;
+    width: number;
+    height: number;
+    class?: string | undefined;
+    label?: string | undefined;
+    padding?: number | undefined;
+    paddingX?: number | undefined;
+    paddingY?: number | undefined;
+    rx?: number | undefined;
+    ry?: number | undefined;
+    shape?: string | undefined;
+  };
+}
diff --git a/lib/layout.js b/lib/layout.js
index 26b07304..20e6eab7 100644
--- a/lib/layout.js
+++ b/lib/layout.js
@@ -17,17 +17,18 @@ var Graph = require("./graphlib").Graph;
 
 module.exports = layout;
 
-function layout(g, opts) {
+function layout(g, inputOpts) {
+  var opts = inputOpts || {};
   var time = opts && opts.debugTiming ? util.time : util.notime;
   time("layout", function() {
     var layoutGraph = 
       time("  buildLayoutGraph", function() { return buildLayoutGraph(g); });
-    time("  runLayout",        function() { runLayout(layoutGraph, time); });
+    time("  runLayout",        function() { runLayout(layoutGraph, time, opts); });
     time("  updateInputGraph", function() { updateInputGraph(g, layoutGraph); });
   });
 }
 
-function runLayout(g, time) {
+function runLayout(g, time, opts) {
   time("    makeSpaceForEdgeLabels", function() { makeSpaceForEdgeLabels(g); });
   time("    removeSelfEdges",        function() { removeSelfEdges(g); });
   time("    acyclic",                function() { acyclic.run(g); });
@@ -42,7 +43,7 @@ function runLayout(g, time) {
   time("    normalize.run",          function() { normalize.run(g); });
   time("    parentDummyChains",      function() { parentDummyChains(g); });
   time("    addBorderSegments",      function() { addBorderSegments(g); });
-  time("    order",                  function() { order(g); });
+  time("    order",                  function() { order(g, opts); });
   time("    insertSelfEdges",        function() { insertSelfEdges(g); });
   time("    adjustCoordinateSystem", function() { coordinateSystem.adjust(g); });
   time("    position",               function() { position(g); });
diff --git a/lib/order/index.js b/lib/order/index.js
index 4ac2d9fa..fa4702a8 100644
--- a/lib/order/index.js
+++ b/lib/order/index.js
@@ -26,7 +26,7 @@ module.exports = order;
  *    1. Graph nodes will have an "order" attribute based on the results of the
  *       algorithm.
  */
-function order(g) {
+function order(g, opts) {
   var maxRank = util.maxRank(g),
     downLayerGraphs = buildLayerGraphs(g, _.range(1, maxRank + 1), "inEdges"),
     upLayerGraphs = buildLayerGraphs(g, _.range(maxRank - 1, -1, -1), "outEdges");
@@ -37,8 +37,9 @@ function order(g) {
   var bestCC = Number.POSITIVE_INFINITY,
     best;
 
+  var constraints = opts.constraints || [];
   for (var i = 0, lastBest = 0; lastBest < 4; ++i, ++lastBest) {
-    sweepLayerGraphs(i % 2 ? downLayerGraphs : upLayerGraphs, i % 4 >= 2);
+    sweepLayerGraphs(i % 2 ? downLayerGraphs : upLayerGraphs, i % 4 >= 2, constraints);
 
     layering = util.buildLayerMatrix(g);
     var cc = crossCount(g, layering);
@@ -46,6 +47,8 @@ function order(g) {
       lastBest = 0;
       best = _.cloneDeep(layering);
       bestCC = cc;
+    } else if (cc === bestCC) {
+      best = _.cloneDeep(layering);
     }
   }
 
@@ -58,8 +61,13 @@ function buildLayerGraphs(g, ranks, relationship) {
   });
 }
 
-function sweepLayerGraphs(layerGraphs, biasRight) {
+function sweepLayerGraphs(layerGraphs, biasRight, constraints) {
   var cg = new Graph();
+
+  _.forEach(constraints, function(constraint) {
+    cg.setEdge(constraint.high, constaint.low);
+  });
+
   _.forEach(layerGraphs, function(lg) {
     var root = lg.graph().root;
     var sorted = sortSubgraph(lg, root, cg, biasRight);
diff --git a/test/order/order-test.js b/test/order/order-test.js
index 9b209f34..60e1896c 100644
--- a/test/order/order-test.js
+++ b/test/order/order-test.js
@@ -20,7 +20,7 @@ describe("order", function() {
     g.setPath(["a", "b", "c"]);
     g.setEdge("b", "d");
     g.setPath(["a", "e", "f"]);
-    order(g);
+    order(g, {});
     var layering = util.buildLayerMatrix(g);
     expect(crossCount(g, layering)).to.equal(0);
   });
@@ -30,7 +30,7 @@ describe("order", function() {
     _.forEach(["a", "d"], function(v) { g.setNode(v, { rank: 1 }); });
     _.forEach(["b", "f", "e"], function(v) { g.setNode(v, { rank: 2 }); });
     _.forEach(["c", "g"], function(v) { g.setNode(v, { rank: 3 }); });
-    order(g);
+    order(g, {});
     var layering = util.buildLayerMatrix(g);
     expect(crossCount(g, layering)).to.equal(0);
   });
@@ -40,7 +40,7 @@ describe("order", function() {
     _.forEach(["b", "e", "g"], function(v) { g.setNode(v, { rank: 2 }); });
     _.forEach(["c", "f", "h"], function(v) { g.setNode(v, { rank: 3 }); });
     g.setNode("d", { rank: 4 });
-    order(g);
+    order(g, {});
     var layering = util.buildLayerMatrix(g);
     expect(crossCount(g, layering)).to.be.lte(1);
   });