Fix floating-point precision issues in Random.num() for integer formats

packages/json-type/src/random/Random.ts

@@ -114,12 +114,13 @@ export class Random {
     let max = Number.MAX_SAFE_INTEGER;
     const schema = type.getSchema();
     const {lt, lte, gt, gte} = schema;
+    const isIntegerFormat = schema.format && ['i8', 'i16', 'i32', 'i64', 'i', 'u8', 'u16', 'u32', 'u64', 'u'].includes(schema.format);
     if (gt !== undefined) min = gt;
     if (gte !== undefined)
       if (gte === lte) return gte;
-      else min = gte + 0.000000000000001;
+      else min = isIntegerFormat ? gte : gte + 0.000000000000001;
     if (lt !== undefined) max = lt;
-    if (lte !== undefined) max = lte - 0.000000000000001;
+    if (lte !== undefined) max = isIntegerFormat ? lte : lte - 0.000000000000001;
     if (min >= max) return max;
     if (schema.format) {
       switch (schema.format) {

packages/json-type/src/random/__tests__/random.spec.ts

@@ -58,6 +58,34 @@ describe('Random', () => {
         }
       });
 
+      test('num with integer format and gte/lte always produces clean integers', () => {
+        // Test u16 format with gte/lte constraints (the configuration that was failing)
+        const type = t.Number({format: 'u16', gte: 1, lte: 65535});
+        for (let i = 0; i < 100; i++) {
+          const value = Random.gen(type);
+          expect(typeof value).toBe('number');
+          expect(Number.isInteger(value)).toBe(true);
+          expect(value).toBeGreaterThanOrEqual(1);
+          expect(value).toBeLessThanOrEqual(65535);
+          // Verify no floating-point artifacts
+          expect(value).toBe(Math.floor(value));
+          validate(type, value);
+        }
+      });
+
+      test('num with all integer formats produces clean integers', () => {
+        const integerFormats = ['i8', 'i16', 'i32', 'u8', 'u16', 'u32'] as const;
+        for (const format of integerFormats) {
+          const type = t.Number({format, gte: 1, lte: 100});
+          for (let i = 0; i < 50; i++) {
+            const value = Random.gen(type);
+            expect(Number.isInteger(value)).toBe(true);
+            expect(value).toBe(Math.floor(value));
+            validate(type, value);
+          }
+        }
+      });
+
       test('bool generates valid booleans', () => {
         const type = t.Boolean();
         for (let i = 0; i < 10; i++) {