change: Remove isFile helper and update File/Blob equality logic

Author: joaoGabriel55

packages/form-core/src/utils.ts

@@ -43,20 +43,6 @@ export function getBy(obj: unknown, path: string | (string | number)[]): any {
   }, obj)
 }
 
-/**
- * Check if an object is a File.
- * @private
- */
-export function isFile(obj: any) {
-  return (
-    obj &&
-    typeof obj === 'object' &&
-    'name' in obj &&
-    'size' in obj &&
-    'type' in obj
-  )
-}
-
 /**
  * Set a value on an object using a path, including dot notation.
  * @private
@@ -66,10 +52,7 @@ export function setBy(obj: any, _path: any, updater: Updater<any>) {
 
   function doSet(parent?: any): any {
     if (!path.length) {
-      return functionalUpdate(
-        isFile(updater) ? { file: updater, uuid: uuid() } : updater,
-        parent,
-      )
+      return functionalUpdate(updater, parent)
     }
 
     const key = path.shift()
@@ -439,15 +422,6 @@ export const isGlobalFormValidationError = (
 }
 
 export function evaluate<T>(objA: T, objB: T) {
-  if (objA instanceof File && objB instanceof File) {
-    return (
-      objA.name === objB.name &&
-      objA.size === objB.size &&
-      objA.type === objB.type &&
-      objA.lastModified === objB.lastModified
-    )
-  }
-
   if (Object.is(objA, objB)) {
     return true
   }
@@ -461,6 +435,18 @@ export function evaluate<T>(objA: T, objB: T) {
     return false
   }
 
+  // Blob (and File, which extends Blob) objects have no own enumerable keys,
+  // so the generic key-comparison below would incorrectly consider any two
+  // Blob/File instances as equal. Fall back to referential identity (already
+  // handled by Object.is above, which returned false).
+  if (
+    typeof Blob !== 'undefined' &&
+    objA instanceof Blob &&
+    objB instanceof Blob
+  ) {
+    return false
+  }
+
   if (objA instanceof Date && objB instanceof Date) {
     return objA.getTime() === objB.getTime()
   }

packages/form-core/tests/FormApi.spec.ts

@@ -4101,35 +4101,30 @@ it('should generate a formId if not provided', () => {
   expect(form.formId.length).toBeGreaterThan(1)
 })
 
-it('should set a file value with uuid when setting a field value with File', () => {
+it('should detect file value changes when setting a different File', () => {
   const form = new FormApi({
     defaultValues: {
-      avatar: undefined,
-    } as { avatar: unknown },
+      avatar: undefined as File | undefined,
+    },
   })
 
   form.mount()
 
   const firstFile = new File(['first'], 'first.png', { type: 'image/png' })
   form.setFieldValue('avatar', firstFile)
-
-  const firstValue = form.state.values.avatar as { file: File; uuid: string }
-
-  expect(firstValue).toBeDefined()
-  expect(isFile(firstValue.file)).toBe(true)
-  expect(firstValue.file.name).toBe('first.png')
-  expect(typeof firstValue.uuid).toBe('string')
-  expect(firstValue.uuid.length).toBeGreaterThan(0)
+  expect(form.getFieldValue('avatar')).toBe(firstFile)
+  expect(form.getFieldValue('avatar')).toBeInstanceOf(File)
+  expect(form.getFieldValue('avatar')!.name).toBe('first.png')
 
   const secondFile = new File(['second'], 'second.png', { type: 'image/png' })
   form.setFieldValue('avatar', secondFile)
+  expect(form.getFieldValue('avatar')).toBe(secondFile)
+  expect(form.getFieldValue('avatar')).toBeInstanceOf(File)
+  expect(form.getFieldValue('avatar')!.name).toBe('second.png')
 
-  const secondValue = form.state.values.avatar as { file: File; uuid: string }
-
-  expect(secondValue.file.name).toBe('second.png')
-  expect(typeof secondValue.uuid).toBe('string')
-  expect(secondValue.uuid.length).toBeGreaterThan(0)
-  expect(secondValue.uuid).not.toBe(firstValue.uuid)
+  // Setting the same file reference again should keep the same value
+  form.setFieldValue('avatar', secondFile)
+  expect(form.getFieldValue('avatar')).toBe(secondFile)
 })
 
 describe('form api event client', () => {

packages/form-core/tests/utils.spec.ts

@@ -753,6 +753,37 @@ describe('evaluate', () => {
     const setB = new Set([1, 2, 4])
     expect(evaluate(setA, setB)).toEqual(false)
   })
+
+  it('should test equality between File/Blob objects', () => {
+    // Same reference should be equal
+    const file1 = new File(['content'], 'test.txt', { type: 'text/plain' })
+    expect(evaluate(file1, file1)).toEqual(true)
+
+    // Different File objects with same metadata should NOT be equal
+    // (referential identity — the user picked a new file)
+    const file2 = new File(['content'], 'test.txt', { type: 'text/plain' })
+    expect(evaluate(file1, file2)).toEqual(false)
+
+    // Different File objects with different metadata
+    const file3 = new File(['other'], 'other.txt', { type: 'image/png' })
+    expect(evaluate(file1, file3)).toEqual(false)
+
+    // Blob objects
+    const blob1 = new Blob(['data'], { type: 'application/octet-stream' })
+    const blob2 = new Blob(['data'], { type: 'application/octet-stream' })
+    expect(evaluate(blob1, blob1)).toEqual(true)
+    expect(evaluate(blob1, blob2)).toEqual(false)
+
+    // File inside an object structure
+    const obj1 = { avatar: file1 }
+    const obj2 = { avatar: file2 }
+    expect(evaluate(obj1, obj2)).toEqual(false)
+
+    // Same file ref inside an object structure
+    const obj3 = { avatar: file1 }
+    const obj4 = { avatar: file1 }
+    expect(evaluate(obj3, obj4)).toEqual(true)
+  })
 })
 
 describe('concatenatePaths', () => {