Use consistent nullish check for array.

sortedUniq.js

@@ -14,7 +14,7 @@ import baseSortedUniq from './.internal/baseSortedUniq.js'
  * // => [1, 2]
  */
 function sortedUniq(array) {
-  return (array && array.length)
+  return (array != null && array.length)
     ? baseSortedUniq(array)
     : []
 }