diff --git a/lib/diagnostic.js b/lib/diagnostic.js
index b585e9b..b9e2a1b 100644
--- a/lib/diagnostic.js
+++ b/lib/diagnostic.js
@@ -70,10 +70,14 @@ function * tokensToDiagnostic (inp, width = 100) {
     if (!token.type.terminal) {
       switch (token.type.name) {
         case 'map':
-          indent.push(token.value * 2)
+          if (token.value) {
+            indent.push(token.value * 2)
+          }
           break
         case 'array':
-          indent.push(token.value)
+          if (token.value) {
+            indent.push(token.value)
+          }
           break
         // TODO: test tags .. somehow
         /* c8 ignore next 5 */