feat(formats): jsonSchemaLoose format should search for enum keyword (#2551)

Author: P0lip

packages/formats/src/__tests__/jsonSchema.test.ts

@@ -80,6 +80,15 @@ describe('JSON Schema format', () => {
       expect(jsonSchemaLoose({ not: {} }, null)).toBe(true);
     });
 
+    it('recognizes by the presence of valid "enum"', () => {
+      expect(jsonSchemaLoose({ enum: ['1'] }, null)).toBe(true);
+      expect(jsonSchemaLoose({ enum: [] }, null)).toBe(true);
+
+      expect(jsonSchemaLoose({ enum: 2 }, null)).toBe(false);
+      expect(jsonSchemaLoose({ enum: {} }, null)).toBe(false);
+      expect(jsonSchemaLoose({ enum: null }, null)).toBe(false);
+    });
+
     describe('mixed', () => {
       it('invalid type but valid combiner', () => {
         expect(jsonSchemaLoose({ type: 'foo', allOf: [] }, null)).toBe(true);

packages/formats/src/jsonSchema.ts

@@ -17,6 +17,8 @@ const hasValidJSONSchemaType = (document: Partial<{ type?: unknown }>): boolean
   return Array.isArray(document.type) && document.type.every(type => KNOWN_JSON_SCHEMA_TYPES.includes(type));
 };
 
+const hasValidJSONSchemaEnumKeyword = (document: Record<string, unknown>): boolean => Array.isArray(document['enum']);
+
 const hasValidJSONSchemaCompoundKeyword = (document: Record<string, unknown>): boolean =>
   KNOWN_JSON_SCHEMA_COMPOUND_KEYWORDS.some(
     combiner => combiner in document && typeof document[combiner] === 'object' && document[combiner] !== null,
@@ -43,7 +45,10 @@ export const jsonSchemaLoose: Format<Record<string, unknown>> = (
   document: unknown,
 ): document is Record<string, unknown> =>
   isPlainObject(document) &&
-  (isJsonSchema(document) || hasValidJSONSchemaType(document) || hasValidJSONSchemaCompoundKeyword(document));
+  (isJsonSchema(document) ||
+    hasValidJSONSchemaType(document) ||
+    hasValidJSONSchemaEnumKeyword(document) ||
+    hasValidJSONSchemaCompoundKeyword(document));
 
 jsonSchemaLoose.displayName = 'JSON Schema (loose)';