fix: respect non-POJO objects in setValues

packages/shared/utils.spec.ts

@@ -0,0 +1,23 @@
+import { getTag, isPlainObject } from './utils';
+
+describe('getTag()', () => {
+  test('should return [object Undefined] for undefined type', () => {
+    const tag = getTag(undefined);
+
+    expect(tag).toBe('[object Undefined]');
+  });
+
+  test('should return [object Null] for null type', () => {
+    const tag = getTag(null);
+
+    expect(tag).toBe('[object Null]');
+  });
+});
+
+describe('isPlainObject()', () => {
+  test('should return true if object has no prototype', () => {
+    const result = isPlainObject(Object.create(null));
+
+    expect(result).toBe(true);
+  });
+});

packages/shared/utils.ts

@@ -23,9 +23,35 @@ export function toNumber(value: string): number | string {
   return isNaN(n) ? value : n;
 }
 
+export function isObjectLike(value: any) {
+  return typeof value === 'object' && value !== null;
+}
+
+export function getTag(value: any) {
+  if (value == null) {
+    return value === undefined ? '[object Undefined]' : '[object Null]';
+  }
+  return Object.prototype.toString.call(value);
+}
+
+// Reference: https://github.com/lodash/lodash/blob/master/isPlainObject.js
+export function isPlainObject(value: any) {
+  if (!isObjectLike(value) || getTag(value) !== '[object Object]') {
+    return false;
+  }
+  if (Object.getPrototypeOf(value) === null) {
+    return true;
+  }
+  let proto = value;
+  while (Object.getPrototypeOf(proto) !== null) {
+    proto = Object.getPrototypeOf(proto);
+  }
+  return Object.getPrototypeOf(value) === proto;
+}
+
 export function merge(target: any, source: any) {
   Object.keys(source).forEach(key => {
-    if (isObject(source[key])) {
+    if (isPlainObject(source[key])) {
       if (!target[key]) {
         target[key] = {};
       }

packages/vee-validate/tests/Form.spec.ts

@@ -1671,6 +1671,31 @@ describe('<Form />', () => {
     expect(inputs[1].value).toBe(values.password);
   });
 
+  test('sets non-plain object field with setValues()', async () => {
+    const wrapper = mountWithHoc({
+      template: `
+      <VForm ref="form">
+        <Field id="nonPlain" name="nonPlain" />
+      </VForm>
+    `,
+    });
+
+    await flushPromises();
+
+    class NonPlain {
+      field = 5;
+    }
+    const nonPlain = new NonPlain();
+    (wrapper.$refs as any)?.form.setValues({
+      nonPlain,
+    });
+
+    const realValues = (wrapper.$refs as any).form.getValues();
+    await flushPromises();
+    expect(realValues.nonPlain).toBeInstanceOf(NonPlain);
+    expect(realValues.nonPlain).toStrictEqual(nonPlain);
+  });
+
   test('handles submit with handleSubmit and passing the event object', async () => {
     const spy = vi.fn();
     const wrapper = mountWithHoc({