diff --git a/package/node/core.js b/package/node/core.js
index 3843c0bf4..8f7745304 100644
--- a/package/node/core.js
+++ b/package/node/core.js
@@ -22,7 +22,7 @@ Blockly.setLocale = function (locale) {
 
 // Override textToDomDocument and provide Node.js alternatives to DOMParser and
 // XMLSerializer.
-if (typeof Blockly.utils.global.DOMParser !== 'function') {
+if (typeof Blockly.utils.global.document !== 'object') {
   Blockly.utils.global.DOMParser = require("jsdom/lib/jsdom/living").DOMParser;
   Blockly.utils.global.XMLSerializer = require("jsdom/lib/jsdom/living").XMLSerializer;
   var doc = Blockly.utils.xml.textToDomDocument(