Fix: avoid push when datalayer doesnt exist (#37)

Author: alinemorelli

dist/TagManager.js

@@ -64,6 +64,7 @@ var TagManager = {
         _ref2$dataLayerName = _ref2.dataLayerName,
         dataLayerName = _ref2$dataLayerName === undefined ? 'dataLayer' : _ref2$dataLayerName;
 
+    if (window[dataLayerName]) return window[dataLayerName].push(_dataLayer);
     var snippets = _Snippets2.default.dataLayer(_dataLayer, dataLayerName);
     var dataScript = this.dataScript(snippets);
     document.head.appendChild(dataScript);

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "react-gtm-module",
-  "version": "2.0.7",
+  "version": "2.0.8",
   "description": "React Google Tag Manager Module",
   "main": "dist/index.js",
   "scripts": {

package.json

@@ -43,7 +43,10 @@ const TagManager = {
     document.body.insertBefore(gtm.noScript(), document.body.childNodes[0])
   },
   dataLayer: function ({dataLayer, dataLayerName = 'dataLayer'}) {
-    window[dataLayerName].push(dataLayer)
+    if (window[dataLayerName]) return window[dataLayerName].push(dataLayer)
+    const snippets = Snippets.dataLayer(dataLayer, dataLayerName)
+    const dataScript = this.dataScript(snippets)
+    document.head.appendChild(dataScript)
   }
 }