feat: enhance validEnumValues function to support array input for message

src/decorator/typechecker/IsEnum.ts

@@ -15,6 +15,9 @@ export function isEnum(value: unknown, entity: any): boolean {
  * Returns the possible values from an enum (both simple number indexed and string indexed enums).
  */
 function validEnumValues(entity: any): string[] {
+  if (Array.isArray(entity)) {
+    return entity;
+  }
   return Object.entries(entity)
     .filter(([key, value]) => isNaN(parseInt(key)))
     .map(([key, value]) => value as string);

test/functional/validation-functions-and-decorators.spec.ts

@@ -918,6 +918,11 @@ describe('IsEnum', () => {
     someProperty: MyStringEnum;
   }
 
+  class MyClassFour {
+    @IsEnum(['first', 'second'])
+    someProperty: 'first' | 'second';
+  }
+
   it('should not fail if validator.validate said that its valid', () => {
     return checkValidValues(new MyClassTwo(), validValues);
   });
@@ -967,6 +972,20 @@ describe('IsEnum', () => {
     const message = 'someProperty must be one of the following values: first, second';
     return checkReturnedError(new MyClassThree(), invalidValues, validationType, message);
   });
+
+  it('should not fail if validator.validate said that its valid (array of strings)', () => {
+    return checkValidValues(new MyClassFour(), validStringValues);
+  });
+
+  it('should fail if validator.validate said that its invalid (array of strings)', () => {
+    return checkInvalidValues(new MyClassFour(), invalidValues);
+  });
+
+  it('should return error with proper message for array of strings', () => {
+    const validationType = 'isEnum';
+    const message = 'someProperty must be one of the following values: first, second';
+    return checkReturnedError(new MyClassFour(), invalidValues, validationType, message);
+  });
 });
 
 describe('IsDivisibleBy', () => {