diff --git a/src/timeunit.ts b/src/timeunit.ts
index 192741ca04..0a79220aee 100644
--- a/src/timeunit.ts
+++ b/src/timeunit.ts
@@ -104,7 +104,7 @@ export function format(timeUnit: TimeUnit, abbreviated = false, field='datum.dat
   }
 
   if (out.length > 0) {
-  // clean up quarter formatting remainders
+  // clean up empty formatting expressions that may have been generated by the quarter time unit
    const template = '{{' + field + ' | time:\'' + out.join(' ') + '\'}}';
    return template.replace(new RegExp('{{' + field + ' \\| time:\'\'}}', 'g'), '');
   } else {