feat: mount method on FormApi

packages/form-core/src/FormApi.ts

@@ -24,8 +24,6 @@ export type FormOptions<TData, ValidatorType> = {
   asyncDebounceMs?: number
   validator?: ValidatorType
   onMount?: ValidateOrFn<TData, ValidatorType>
-  onMountAsync?: ValidateAsyncFn<TData, ValidatorType>
-  onMountAsyncDebounceMs?: number
   onChange?: ValidateOrFn<TData, ValidatorType>
   onChangeAsync?: ValidateAsyncFn<TData, ValidatorType>
   onChangeAsyncDebounceMs?: number
@@ -170,6 +168,18 @@ export class FormApi<TFormData, ValidatorType> {
     this.update(opts || {})
   }
 
+  mount = () => {
+    if (typeof this.options.onMount === 'function') {
+      return this.options.onMount(this.state.values, this)
+    }
+    if (this.options.validator) {
+      return (this.options.validator as Validator<TFormData>)().validate(
+        this.state.values,
+        this.options.onMount,
+      )
+    }
+  }
+
   update = (options?: FormOptions<TFormData, ValidatorType>) => {
     if (!options) return
 

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

@@ -6,7 +6,7 @@ import { FieldApi } from '../FieldApi'
 describe('form api', () => {
   it('should get default form state', () => {
     const form = new FormApi()
-
+    form.mount()
     expect(form.state).toEqual({
       values: {},
       fieldMeta: {},
@@ -31,7 +31,7 @@ describe('form api', () => {
         name: 'test',
       },
     })
-
+    form.mount()
     expect(form.state).toEqual({
       values: {
         name: 'test',
@@ -58,7 +58,7 @@ describe('form api', () => {
         submissionAttempts: 30,
       },
     })
-
+    form.mount()
     expect(form.state).toEqual({
       values: {},
       fieldMeta: {},
@@ -83,7 +83,7 @@ describe('form api', () => {
         name: 'test',
       },
     })
-
+    form.mount()
     form.update({
       defaultValues: {
         name: 'other',
@@ -119,7 +119,7 @@ describe('form api', () => {
         name: 'test',
       },
     })
-
+    form.mount()
     form.setFieldValue('name', 'other')
     form.state.submissionAttempts = 300
 
@@ -151,7 +151,7 @@ describe('form api', () => {
         name: 'test',
       },
     })
-
+    form.mount()
     expect(form.getFieldValue('name')).toEqual('test')
   })
 
@@ -161,7 +161,7 @@ describe('form api', () => {
         name: 'test',
       },
     })
-
+    form.mount()
     form.setFieldValue('name', 'other')
 
     expect(form.getFieldValue('name')).toEqual('other')
@@ -173,7 +173,7 @@ describe('form api', () => {
         names: ['test'],
       },
     })
-
+    form.mount()
     form.pushFieldValue('names', 'other')
 
     expect(form.getFieldValue('names')).toStrictEqual(['test', 'other'])
@@ -185,7 +185,7 @@ describe('form api', () => {
         names: ['one', 'two', 'three'],
       },
     })
-
+    form.mount()
     form.insertFieldValue('names', 1, 'other')
 
     expect(form.getFieldValue('names')).toStrictEqual(['one', 'other', 'three'])
@@ -197,7 +197,7 @@ describe('form api', () => {
         names: ['one', 'two', 'three'],
       },
     })
-
+    form.mount()
     form.removeFieldValue('names', 1)
 
     expect(form.getFieldValue('names')).toStrictEqual(['one', 'three'])
@@ -209,7 +209,7 @@ describe('form api', () => {
         names: ['one', 'two', 'three'],
       },
     })
-
+    form.mount()
     form.swapFieldValues('names', 1, 2)
 
     expect(form.getFieldValue('names')).toStrictEqual(['one', 'three', 'two'])
@@ -221,7 +221,7 @@ describe('form api', () => {
         name: 'test',
       },
     })
-
+    form.mount()
     form.setFieldValue('name', 'other')
 
     expect(form.getFieldValue('name')).toEqual('other')
@@ -237,7 +237,7 @@ describe('form api', () => {
         name: 'test',
       },
     })
-
+    form.mount()
     expect(form.getFieldValue('name')).toEqual('test')
 
     form.update({
@@ -255,7 +255,7 @@ describe('form api', () => {
         name: 'one',
       },
     })
-
+    form.mount()
     expect(form.getFieldValue('name')).toEqual('one')
 
     form.setFieldValue('name', 'two', { touch: true })
@@ -297,6 +297,8 @@ describe('form api', () => {
       onChange: (v) => (v.length > 0 ? undefined : 'required'),
     })
 
+    form.mount()
+
     field.mount()
 
     field.handleChange('one')

packages/react-form/src/tests/useForm.test.tsx

@@ -124,4 +124,37 @@ describe('useForm', () => {
       expect(getByText('Submitted data: OtherName')).toBeInTheDocument(),
     )
   })
+
+  it('should run on form mount', async () => {
+    function Comp() {
+      const [formMounted, setFormMounted] = React.useState(false)
+      const [mountForm, setMountForm] = React.useState(false)
+
+      const form = useForm({
+        defaultValues: {
+          firstName: 'FirstName',
+        },
+        onMount: () => {
+          setFormMounted(true)
+          return undefined
+        },
+      })
+
+      return (
+        <>
+          {mountForm ? (
+            <form.Provider>
+              <h1>{formMounted ? 'Form mounted' : 'Not mounted'}</h1>
+            </form.Provider>
+          ) : (
+            <button onClick={() => setMountForm(true)}>Mount form</button>
+          )}
+        </>
+      )
+    }
+
+    const { getByText } = render(<Comp />)
+    await user.click(getByText('Mount form'))
+    await waitFor(() => expect(getByText('Form mounted')).toBeInTheDocument())
+  })
 })

packages/react-form/src/useForm.tsx

@@ -31,6 +31,7 @@ export function useForm<TData, FormValidator>(
     const api = new FormApi<TData>(opts)
 
     api.Provider = function Provider(props) {
+      useIsomorphicLayoutEffect(formApi.mount, [])
       return <formContext.Provider {...props} value={{ formApi: api }} />
     }
     api.Field = Field as any

packages/solid-form/src/createForm.tsx

@@ -1,6 +1,6 @@
 import type { FormOptions, FormState } from '@tanstack/form-core'
 import { FormApi, functionalUpdate } from '@tanstack/form-core'
-import { createComputed, type JSXElement } from 'solid-js'
+import { createComputed, onMount, type JSXElement } from 'solid-js'
 import { useStore } from '@tanstack/solid-store'
 import {
   Field,
@@ -35,6 +35,7 @@ export function createForm<TData, FormValidator>(
   const formApi = new FormApi<TData, FormValidator>(options)
 
   formApi.Provider = function Provider(props) {
+    onMount(formApi.mount)
     return <formContext.Provider {...props} value={{ formApi: formApi }} />
   }
   formApi.Field = Field as any

packages/solid-form/src/tests/createForm.test.tsx

@@ -2,6 +2,7 @@ import { render, screen, waitFor } from '@solidjs/testing-library'
 import '@testing-library/jest-dom'
 import userEvent from '@testing-library/user-event'
 import { createFormFactory, createForm } from '..'
+import { Show, createSignal } from 'solid-js'
 
 const user = userEvent.setup()
 
@@ -113,4 +114,37 @@ describe('createForm', () => {
     await user.click(getByText('Submit'))
     expect(submittedData?.firstName).toEqual('OtherName')
   })
+
+  it('should run on form mount', async () => {
+    const [formMounted, setFormMounted] = createSignal(false)
+    const [mountForm, setMountForm] = createSignal(false)
+    function Comp() {
+      const form = createForm(() => ({
+        defaultValues: {
+          firstName: 'FirstName',
+        },
+        onMount: () => {
+          setFormMounted(true)
+          return undefined
+        },
+      }))
+
+      return (
+        <Show
+          when={mountForm()}
+          fallback={
+            <button onClick={() => setMountForm(true)}>Mount form</button>
+          }
+        >
+          <form.Provider>
+            <h1>Form mounted</h1>
+          </form.Provider>
+        </Show>
+      )
+    }
+
+    const { getByText } = render(() => <Comp />)
+    await user.click(getByText('Mount form'))
+    expect(formMounted()).toBe(true)
+  })
 })

packages/vue-form/src/tests/useForm.test.tsx

@@ -138,4 +138,35 @@ describe('useForm', () => {
       expect(getByText('Submitted data: OtherName')).toBeInTheDocument(),
     )
   })
+
+  it('should run on form mount', async () => {
+    const Comp = defineComponent(() => {
+      const formMounted = ref(false)
+      const mountForm = ref(false)
+
+      const form = useForm({
+        defaultValues: {
+          firstName: 'FirstName',
+        },
+        onMount: () => {
+          formMounted.value = true
+          return undefined
+        },
+      })
+      form.provideFormContext()
+
+      return () =>
+        mountForm.value ? (
+          <form.Provider>
+            <h1>{formMounted.value ? 'Form mounted' : 'Not mounted'}</h1>
+          </form.Provider>
+        ) : (
+          <button onClick={() => (mountForm.value = true)}>Mount form</button>
+        )
+    })
+
+    const { getByText, findByText } = render(Comp)
+    await user.click(getByText('Mount form'))
+    expect(await findByText('Form mounted')).toBeInTheDocument()
+  })
 })

packages/vue-form/src/useForm.tsx

@@ -7,6 +7,7 @@ import {
   type SlotsType,
   type SetupContext,
   defineComponent,
+  onMounted,
 } from 'vue-demi'
 
 declare module '@tanstack/form-core' {
@@ -39,6 +40,7 @@ export function useForm<TData, FormValidator>(
 
     api.Provider = defineComponent(
       (_, context) => {
+        onMounted(formApi.mount)
         provideFormContext({ formApi: formApi as never })
         return () => context.slots.default!()
       },