Add isBeforeDate, isAfterDate, isSameDate

snippets/hz.md

@@ -11,7 +11,7 @@ Omit the second argument, `iterations`, to use the default of 100 iterations.
 const hz = (fn, iterations = 100) => {
   const before = performance.now();
   for (let i = 0; i < iterations; i++) fn();
-  return (1000 * iterations) / (performance.now() - before);
+  return 1000 * iterations / (performance.now() - before);
 };
 ```