fix: form should now be aware of field unmounting

* Add basic tests for arrays

* Ran prettier

* Ran prettier

* Add new test for bug

* Fix bug regarding preserved values even if field is umounted

* Run prettier

* Update store subscription when removingFields

packages/form-core/src/FormApi.ts

@@ -360,8 +360,11 @@ export class FormApi<TFormData, ValidatorType> {
   }
 
   deleteField = <TField extends DeepKeys<TFormData>>(field: TField) => {
-    delete this.state.values[field as keyof TFormData]
-    delete this.state.fieldMeta[field]
+    const newState = { ...this.state }
+    delete newState.values[field as keyof TFormData]
+    delete newState.fieldMeta[field]
+
+    this.store.setState((_) => newState)
   }
 
   pushFieldValue = <TField extends DeepKeys<TFormData>>(

packages/form-core/src/tests/FieldApi.spec.ts

@@ -1,4 +1,4 @@
-import { expect } from 'vitest'
+import { expect, vitest } from 'vitest'
 
 import { FormApi } from '../FormApi'
 import { FieldApi } from '../FieldApi'
@@ -597,11 +597,17 @@ describe('field api', () => {
     })
 
     const unmount = field.mount()
+    const callback = vitest.fn()
+    const subscription = form.store.subscribe(callback)
     unmount()
     const info = form.getFieldInfo(field.name)
+    subscription()
     expect(info.instances[field.uid]).toBeUndefined()
     expect(Object.keys(info.instances).length).toBe(0)
 
+    // Check that form store has been updated
+    expect(callback).toHaveBeenCalledOnce()
+
     // Field should have been removed from the form as well
     expect(form.state.values.name).toBeUndefined()
     expect(form.state.fieldMeta.name).toBeUndefined()