Sync README and type declaration docs

sindresorhus · Oct 19, 2020 · e653497 · e653497
1 parent 69de916
commit e653497
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/readme.md b/readme.md
@@ -245,6 +245,8 @@ The `default` value set in `boolean` flags take precedence over `booleanDefault`
 
 _Note: If used in conjunction with `isMultiple`, the default flag value is set to `[]`._
 
+__Caution: Explicitly specifying undefined for `booleanDefault` has different meaning from omitting key itself.__
+
 Example:
 
 ```js