Do not create properties with empty name

src/converter/plugins/StringUnionTypePlugin.ts

@@ -69,9 +69,10 @@ export function convertStringUnionType(
             checkCoverageService?.cover(literal)
 
             const value = literal.text
-            const key = value === ""
+            const valueAsIdentifier = identifier(value)
+            const key = (value === "") || (valueAsIdentifier === "")
                 ? "`_`"
-                : identifier(value)
+                : valueAsIdentifier
             return [key, value] as const
         })
 

test/functional/base/generated/union/stringEnum.kt

@@ -17,6 +17,21 @@ val multipartFormData: FormEncType
 }
 
 external fun switcher(): SwitcherResult
+
+sealed external interface Operator {
+companion object {
+@seskar.js.JsValue("")
+val `_`: Operator
+/*
+Duplicated names were generated:
+`_` for "="
+`_` for "<"
+`_` for ">"
+`_` for "<="
+`_` for ">="
+*/
+}
+}
 sealed external interface SwitcherResult {
 companion object {
 @seskar.js.JsValue("on")

test/functional/base/lib/union/stringEnum.d.ts

@@ -1,3 +1,5 @@
 export declare type FormEncType = "application/x-www-form-urlencoded" | "multipart/form-data";
 
 export declare function switcher(): "on" | "off"
+
+export declare type Operator = "" | "=" | "<" | ">" | "<=" | ">=";