diff --git a/lib/build-graph.js b/lib/build-graph.js
index <HASH>..<HASH> 100644
--- a/lib/build-graph.js
+++ b/lib/build-graph.js
@@ -11,7 +11,7 @@ function buildGraph(parseTree) {
       defaultStack = [{ node: {}, edge: {} }],
       id = parseTree.id,
       g = new Graph({ directed: isDirected, multigraph: isMultigraph, compound: true });
-      g.setGraph(id == null ? {} : {id: id});
+      g.setGraph(id === null ? {} : {id: id});
   _.each(parseTree.stmts, function(stmt) { handleStmt(g, stmt, defaultStack); });
   return g;
 }
diff --git a/test/read-one-test.js b/test/read-one-test.js
index <HASH>..<HASH> 100644
--- a/test/read-one-test.js
+++ b/test/read-one-test.js
@@ -39,7 +39,7 @@ describe("read", function() {
       var g = read("digraph foobar {}");
       expect(g.nodeCount()).to.equal(0);
       expect(g.edgeCount()).to.equal(0);
-      expect(g.graph()).to.eql({id: 'foobar'});
+      expect(g.graph()).to.eql({id: "foobar"});
       expect(g.isDirected()).to.be.true;
     });
Fix code style for graph id patch