diff -r 1b8b29c0e95c -r 245b4df137d3 common/corpus-common-addon/addon/components/doc-subject.js
--- a/common/corpus-common-addon/addon/components/doc-subject.js	Tue Dec 13 23:30:54 2016 +0100
+++ b/common/corpus-common-addon/addon/components/doc-subject.js	Fri Dec 16 17:43:07 2016 +0100
@@ -3,39 +3,44 @@
 import layout from '../templates/components/doc-subject';
 
 export default Ember.Component.extend({
-    layout: layout,
-    tagName: "span",
-    displayLabel: Ember.computed('label', 'resolvedLabel', function() {
-      return this.get('label') || this.get('resolvedLabel');
-    }),
-    bnfResolver: Ember.inject.service(),
+  layout: layout,
+  tagName: 'span',
+  displayLabel: Ember.computed('label', 'resolvedLabel', function () {
+    return this.get('label') || this.get('resolvedLabel');
+  }),
+  bnfResolver: Ember.inject.service(),
 
-    _resolveBnfIds: Ember.on('init', Ember.observer('url', 'label', function() {
-      if(this.get('label')) {
-        if (!(this.get('isDestroyed') || this.get('isDestroying'))) {
-          this.set('resolvedLabel', this.get('label'));
-        }
-        return;
+  _resolveBnfIds: Ember.on('init', Ember.observer('url', 'label', function () {
+    if (this.get('label')) {
+      if (!(this.get('isDestroyed') || this.get('isDestroying'))) {
+        this.set('resolvedLabel', this.get('label'));
       }
-      this.get('bnfResolver').getLabel(this.get('url')).then(function(str) {
-        if (!(this.get('isDestroyed') || this.get('isDestroying'))) {
-          this.set('resolvedLabel', str);
-        }
-      }.bind(this));
-    })),
+
+      return;
+    }
+    if (this.get('bnfResolver')) {
+      this.get('bnfResolver').getLabel(this.get('url'))
+        .then(function (str) {
+          if (!(this.get('isDestroyed') || this.get('isDestroying'))) {
+            this.set('resolvedLabel', str);
+          }
+        }.bind(this));
+    }
+  })),
 
-    code: Ember.computed('url', function() {
-      var rawSubject = this.get('url');
-      if(rawSubject) {
-        if(rawSubject.startsWith(constants.BNF_BASE_URL)) {
-          return rawSubject.substr(constants.BNF_BASE_URL.length);
-        }
-        else if (rawSubject.startsWith(constants.BNF_ARK_BASE_URL)) {
-          return rawSubject.substr(constants.BNF_ARK_BASE_URL.length);
-        }
+  code: Ember.computed('url', function () {
+    const rawSubject = this.get('url');
+
+    if (rawSubject) {
+      if (rawSubject.startsWith(constants.BNF_BASE_URL)) {
+        return rawSubject.substr(constants.BNF_BASE_URL.length);
+      } else if (rawSubject.startsWith(constants.BNF_ARK_BASE_URL)) {
+        return rawSubject.substr(constants.BNF_ARK_BASE_URL.length);
       }
-      return rawSubject;
-    }),
-    isSubjectLink: Ember.computed.match('url', /^http\:\/\//)
+    }
+
+    return rawSubject;
+  }),
+  isSubjectLink: Ember.computed.match('url', /^http\:\/\//)
 
 });