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The injectForm function creates and manages forms in Angular applications using TanStack Form.

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Import

import { injectForm } from '@tanstack/angular-form'

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Signature

function injectForm<
  TFormData,
  TOnMount extends undefined | FormValidateOrFn<TFormData>,
  TOnChange extends undefined | FormValidateOrFn<TFormData>,
  TOnChangeAsync extends undefined | FormAsyncValidateOrFn<TFormData>,
  TOnBlur extends undefined | FormValidateOrFn<TFormData>,
  TOnBlurAsync extends undefined | FormAsyncValidateOrFn<TFormData>,
  TOnSubmit extends undefined | FormValidateOrFn<TFormData>,
  TOnSubmitAsync extends undefined | FormAsyncValidateOrFn<TFormData>,
  TOnDynamic extends undefined | FormValidateOrFn<TFormData>,
  TOnDynamicAsync extends undefined | FormAsyncValidateOrFn<TFormData>,
  TOnServer extends undefined | FormAsyncValidateOrFn<TFormData>,
  TSubmitMeta,
>(
  opts?: FormOptions<
    TFormData,
    TOnMount,
    TOnChange,
    TOnChangeAsync,
    TOnBlur,
    TOnBlurAsync,
    TOnSubmit,
    TOnSubmitAsync,
    TOnDynamic,
    TOnDynamicAsync,
    TOnServer,
    TSubmitMeta
  >,
): FormApi<...>

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Parameters

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opts
FormOptions<TFormData>
Optional configuration object for the form.
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opts.defaultValues
TFormData
Initial values for the form fields.
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opts.onSubmit
(values: FormSubmitData<TFormData>) => void | Promise<void>
Callback function called when the form is submitted.
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opts.validators
FormValidators<TFormData>
Validation functions for the form.
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opts.validators.onChange
FormValidateOrFn<TFormData>
Validator that runs on every change.
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opts.validators.onChangeAsync
FormAsyncValidateOrFn<TFormData>
Async validator that runs on change with debouncing.
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opts.validators.onBlur
FormValidateOrFn<TFormData>
Validator that runs when the form loses focus.
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opts.validators.onMount
FormValidateOrFn<TFormData>
Validator that runs when the form is mounted.

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Return Value

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api
FormApi<TFormData>
The form API instance.
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handleSubmit
() => void
Function to trigger form submission.
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reset
() => void
Function to reset the form to its initial state.
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state
FormState<TFormData>
Current state of the form including values, errors, and validation status.
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store
Store<FormState<TFormData>>
The underlying store for the form state.
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mount
() => () => void
Mount the form and return a cleanup function.

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Usage Example

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Basic Form

import { Component } from '@angular/core'
import { injectForm, injectStore, TanStackField } from '@tanstack/angular-form'
import type { FieldValidateFn } from '@tanstack/angular-form'

interface FormData {
  firstName: string
  lastName: string
}

@Component({
  selector: 'app-root',
  standalone: true,
  imports: [TanStackField],
  template: `
    <form (submit)="handleSubmit($event)">
      <div>
        <ng-container
          [tanstackField]="form"
          name="firstName"
          [validators]="{ onChange: firstNameValidator }"
          #firstName="field"
        >
          <label [for]="firstName.api.name">First Name:</label>
          <input
            [id]="firstName.api.name"
            [name]="firstName.api.name"
            [value]="firstName.api.state.value"
            (blur)="firstName.api.handleBlur()"
            (input)="firstName.api.handleChange($any($event).target.value)"
          />
          @if (firstName.api.state.meta.isTouched) {
            @for (error of firstName.api.state.meta.errors; track $index) {
              <div style="color: red">
                {{ error }}
              </div>
            }
          }
        </ng-container>
      </div>

      <button type="submit" [disabled]="!canSubmit()">
        {{ isSubmitting() ? '...' : 'Submit' }}
      </button>
    </form>
  `,
})
export class AppComponent {
  firstNameValidator: FieldValidateFn<FormData, string, any> = ({ value }) =>
    !value
      ? 'A first name is required'
      : value.length < 3
        ? 'First name must be at least 3 characters'
        : undefined

  form = injectForm<FormData>({
    defaultValues: {
      firstName: '',
      lastName: '',
    },
    onSubmit({ value }) {
      console.log('Form submitted:', value)
    },
  })

  canSubmit = injectStore(this.form, (state) => state.canSubmit)
  isSubmitting = injectStore(this.form, (state) => state.isSubmitting)

  handleSubmit(event: SubmitEvent) {
    event.preventDefault()
    event.stopPropagation()
    this.form.handleSubmit()
  }
}

​
Form with Async Validation

import { Component } from '@angular/core'
import { injectForm, TanStackField } from '@tanstack/angular-form'
import type { FieldValidateAsyncFn } from '@tanstack/angular-form'

@Component({
  selector: 'app-form',
  standalone: true,
  imports: [TanStackField],
  template: `
    <form (submit)="handleSubmit($event)">
      <ng-container
        [tanstackField]="form"
        name="username"
        [validators]="{
          onChangeAsync: usernameAsyncValidator,
          onChangeAsyncDebounceMs: 500,
        }"
        #username="field"
      >
        <input
          [value]="username.api.state.value"
          (input)="username.api.handleChange($any($event).target.value)"
        />
        @if (username.api.state.meta.isValidating) {
          <p>Validating...</p>
        }
      </ng-container>
    </form>
  `,
})
export class FormComponent {
  usernameAsyncValidator: FieldValidateAsyncFn<any, string, any> = async ({
    value,
  }) => {
    await new Promise((resolve) => setTimeout(resolve, 1000))
    return value === 'taken' ? 'Username already taken' : undefined
  }

  form = injectForm({
    defaultValues: {
      username: '',
    },
    onSubmit({ value }) {
      console.log(value)
    },
  })

  handleSubmit(event: SubmitEvent) {
    event.preventDefault()
    this.form.handleSubmit()
  }
}

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See Also

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