fix(guards): objects with index signature as additional properties

Author: vmasek

src/parser.ts

@@ -378,6 +378,12 @@ function parseInterfaceProperties(
                 ? `typeof item === '${type}'`
                 : `is${prop.typescriptType || typescriptType}(item)`
             }))`
+          : name === ADDITIONAL_PROPERTIES_KEY
+          ? `Object.values(arg).every((item: unknown) => ${
+              isPrimitiveType
+                ? `typeof item === '${type}'`
+                : `is${typescriptType}(item)`
+            })`
           : `${
               prop.isPrimitiveType || isPrimitiveType
                 ? `typeof arg.${prop.name || name} === '${

tests/custom/api/guards/index.ts

@@ -119,7 +119,7 @@ export function isDictionary(arg: any): arg is models.Dictionary {
   arg != null &&
   typeof arg === 'object' &&
     // [key: string]: DictionaryItem
-    ( isDictionaryItem(arg.[key: string]) ) &&
+    ( Object.values(arg).every((item: unknown) => isDictionaryItem(item)) ) &&
 
   true
   );
@@ -130,7 +130,7 @@ export function isDictionaryItem(arg: any): arg is models.DictionaryItem {
   arg != null &&
   typeof arg === 'object' &&
     // [key: string]: number
-    ( typeof arg.[key: string] === 'number' ) &&
+    ( Object.values(arg).every((item: unknown) => typeof item === 'number') ) &&
 
   true
   );

tests/github/api/guards/index.ts

@@ -942,7 +942,7 @@ export function isLanguages(arg: any): arg is models.Languages {
   arg != null &&
   typeof arg === 'object' &&
     // [key: string]: number
-    ( typeof arg.[key: string] === 'number' ) &&
+    ( Object.values(arg).every((item: unknown) => typeof item === 'number') ) &&
 
   true
   );