Change wrapper to have undefined as classKeys

Author: Andrii Kirmas

src/basic.ts

@@ -42,7 +42,7 @@ function _classNaming(
   const className = joinWithLead(propagate, dehash(classes))  
   , host: ClassNamingCall = classes => _classNaming(classes, className)
 
-  return wrapper(className, [], host)
+  return wrapper(className, undefined, host)
 }
 
 type ClassNamingChain = ClassNamingCall & {

src/core.ts

@@ -13,9 +13,14 @@ export {
   joinWithLead
 }
 
-function wrapper<T>(className: Falsy|ClassValue, classKeys: string[], destination: T) {
+function wrapper<T>(
+  className: Parameters<typeof joinWithLead>[0],
+  classKeys: Parameters<typeof joinWithLead>[1],
+  destination: T
+) {
   //@ts-expect-error
-  destination[classNameKey] = joinWithLead(className, classKeys)
+  destination[classNameKey]
+  = joinWithLead(className, classKeys)
 
   return stringifyClassNamed(destination as T & ClassNamed)
 }
@@ -53,13 +58,13 @@ function truthyKeys<T>(source: T) {
   return filtered
 }
 
-//TODO Consider undefined
-function joinWithLead(value: Falsy|ClassValue, arr: readonly string[]) :string {
+//TODO Consider returning `undefined` on empty string
+function joinWithLead(value: Falsy|ClassValue, arr: undefined| readonly string[]) : string {
   const str1 = value || ""
-  if (!arr.length)
+  if (!(arr && arr.length))
     return str1
 
-  const str2  = arr.join(" ")
+  const str2 = arr.join(" ")
   if (!str1)
     return str2