Add require to d3.js

Makefile

@@ -1,5 +1,6 @@
 MOD = dagre-d3
 
+NODE = node
 NPM = npm
 BROWSERIFY = ./node_modules/browserify/bin/cmd.js
 ISTANBUL = ./node_modules/istanbul/lib/cli.js
@@ -37,7 +38,7 @@ lib/version.js: package.json
 $(DIRS):
 	@mkdir -p $@
 
-test: browser-test demo-test
+test: browser-test demo-test node-test
 
 browser-test: $(BUILD_FILES)
 	$(KARMA) start --single-run $(KARMA_OPTS)
@@ -46,6 +47,9 @@ browser-test: $(BUILD_FILES)
 demo-test: test/demo-test.js | $(BUILD_FILES)
 	$(PHANTOMJS) $<
 
+node-test: test/node-test.js | $(BUILD_FILES)
+	$(NODE) $<
+
 bower.json: package.json src/release/make-bower.json.js
 	@src/release/make-bower.json.js > $@
 

lib/d3.js

@@ -1,2 +1,18 @@
 // Stub to get D3 either via NPM or from the global object
-module.exports = window.d3;
+var d3;
+
+if (!d3) {
+  if (require) {
+    try {
+      d3 = require("d3");
+    }
+    catch (e) {
+    }
+  }
+}
+
+if (!d3) {
+  d3 = window.d3;
+}
+
+module.exports = d3;

lib/render.js

@@ -1,4 +1,5 @@
 var _ = require("./lodash"),
+    d3 = require("./d3"),
     layout = require("./dagre").layout;
 
 module.exports = render;

test/node-test.js

@@ -0,0 +1,2 @@
+var dagreD3 = require("../build/dist/dagre-d3");
+var dagreD3Core = require("../build/dist/dagre-d3.core");