diff --git a/extensions/amp-story-panning-media/0.1/test/validator-amp-story-panning-media.out b/extensions/amp-story-panning-media/0.1/test/validator-amp-story-panning-media.out
index 0f005b7cb5a4..d5a5b2f47683 100644
--- a/extensions/amp-story-panning-media/0.1/test/validator-amp-story-panning-media.out
+++ b/extensions/amp-story-panning-media/0.1/test/validator-amp-story-panning-media.out
@@ -73,4 +73,4 @@ PASS
 |        </amp-story-page>
 |      </amp-story>
 |    </body>
-|  </html>
\ No newline at end of file
+|  </html>
diff --git a/validator/validator_gen_js.py b/validator/validator_gen_js.py
index e87ec09c42a2..afe3707da238 100644
--- a/validator/validator_gen_js.py
+++ b/validator/validator_gen_js.py
@@ -484,6 +484,22 @@ def PrintEnumFor(enum_desc, out):
       (LocalModuleName(enum_desc.full_name), ','.join([
           '%s.%s' % (LocalModuleName(enum_desc.full_name), n) for n in names
       ])))
+  out.Line('/** @type (!Object<%s, number>) */' %
+           LocalModuleName(enum_desc.full_name))
+  out.Line('%s_NumberByName = {' % LocalModuleName(enum_desc.full_name))
+  out.PushIndent(2)
+  for v in enum_desc.values:
+    out.Line("'%s': %s," % (v.name, v.number))
+  out.PopIndent()
+  out.Line('};')
+  out.Line('/** @type (!Object<number, %s>) */' %
+           LocalModuleName(enum_desc.full_name))
+  out.Line('%s_NameByNumber = {' % LocalModuleName(enum_desc.full_name))
+  out.PushIndent(2)
+  for v in enum_desc.values:
+    out.Line("%s: '%s'," % (v.number, v.name))
+  out.PopIndent()
+  out.Line('};')
 
 
 def TagSpecName(tag_spec):