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Documentation Index

Fetch the complete documentation index at: https://mintlify.com/tanstack/form/llms.txt

Use this file to discover all available pages before exploring further.

Get started with TanStack Form in Svelte by creating a form instance and connecting it to your form fields.

​
Installation

Install the Svelte adapter for TanStack Form: 
npm install @tanstack/svelte-form

​
Your First Form

The bare minimum to get started is to create a form and add a field using createForm.
1
Create a Form Instance
2
Use createForm to create a form instance with default values and a submit handler:
3
<script>
  import { createForm } from '@tanstack/svelte-form'

  const form = createForm(() => ({
    defaultValues: {
      fullName: '',
    },
    onSubmit: async ({ value }) => {
      // Do something with form data
      console.log(value)
    },
  }))
</script>
4
The createForm function returns a reactive form store that automatically updates your UI when form state changes.
5
Create the Form Element
6
Create a form element that handles submission:
7
<form
  onsubmit={(e) => {
    e.preventDefault()
    e.stopPropagation()
    form.handleSubmit()
  }}
>
  <!-- Fields will go here -->
</form>
8
Add a Field
9
Use the form.Field component with Svelte’s snippet syntax to create form fields:
10
<form.Field name="fullName">
  {#snippet children(field)}
    <input
      name={field.name}
      value={field.state.value}
      onblur={field.handleBlur}
      oninput={(e) => field.handleChange(e.target.value)}
    />
  {/snippet}
</form.Field>

​
Complete Example

Here’s a complete working form with validation: 
<script>
  import { createForm } from '@tanstack/svelte-form'

  const form = createForm(() => ({
    defaultValues: {
      fullName: '',
    },
    onSubmit: async ({ value }) => {
      console.log(value)
    },
  }))
</script>

<div>
  <h1>Simple Form Example</h1>
  <form
    onsubmit={(e) => {
      e.preventDefault()
      e.stopPropagation()
      form.handleSubmit()
    }}
  >
    <div>
      <form.Field name="fullName">
        {#snippet children(field)}
          <input
            name={field.name}
            value={field.state.value}
            onblur={field.handleBlur}
            oninput={(e) => field.handleChange(e.target.value)}
          />
        {/snippet}
      </form.Field>
    </div>
    <button type="submit">Submit</button>
  </form>
</div>

​
Example with Multiple Fields

Here’s a more complete example with multiple fields and validation: 
<script lang="ts">
  import { createForm } from '@tanstack/svelte-form'

  const form = createForm(() => ({
    defaultValues: {
      firstName: '',
      lastName: '',
      employed: false,
      jobTitle: '',
    },
    onSubmit: async ({ value }) => {
      alert(JSON.stringify(value))
    },
  }))
</script>

<form
  id="form"
  onsubmit={(e) => {
    e.preventDefault()
    e.stopPropagation()
    form.handleSubmit()
  }}
>
  <h1>TanStack Form - Svelte Demo</h1>

  <form.Field
    name="firstName"
    validators={{
      onChange: ({ value }) =>
        value.length < 3 ? 'Not long enough' : undefined,
    }}
  >
    {#snippet children(field)}
      <div>
        <label for={field.name}>First Name</label>
        <input
          id={field.name}
          type="text"
          placeholder="First Name"
          value={field.state.value}
          onblur={() => field.handleBlur()}
          oninput={(e: Event) => {
            const target = e.target as HTMLInputElement
            field.handleChange(target.value)
          }}
        />
        {#if field.state.meta.errors}
          <em>{field.state.meta.errors[0]}</em>
        {/if}
      </div>
    {/snippet}
  </form.Field>

  <form.Field
    name="lastName"
    validators={{
      onChange: ({ value }) =>
        value.length < 3 ? 'Not long enough' : undefined,
    }}
  >
    {#snippet children(field)}
      <div>
        <label for={field.name}>Last Name</label>
        <input
          id={field.name}
          type="text"
          placeholder="Last Name"
          value={field.state.value}
          onblur={() => field.handleBlur()}
          oninput={(e: Event) => {
            const target = e.target as HTMLInputElement
            field.handleChange(target.value)
          }}
        />
        {#if field.state.meta.errors}
          <em>{field.state.meta.errors[0]}</em>
        {/if}
      </div>
    {/snippet}
  </form.Field>

  <div>
    <form.Subscribe
      selector={(state) => ({
        canSubmit: state.canSubmit,
        isSubmitting: state.isSubmitting,
      })}
    >
      {#snippet children({ canSubmit, isSubmitting })}
        <button type="submit" disabled={!canSubmit}>
          {isSubmitting ? 'Submitting' : 'Submit'}
        </button>
      {/snippet}
    </form.Subscribe>
    <button type="button" onclick={() => form.reset()}>
      Reset
    </button>
  </div>
</form>

​
Key Concepts

​
Form Instance

The form instance returned by createForm is a reactive Svelte store that provides:
  • form.Field - Component for creating form fields
  • form.Subscribe - Component for subscribing to form state
  • form.handleSubmit() - Method to submit the form
  • form.reset() - Method to reset the form to default values
  • form.useStore() - Hook to subscribe to specific form state

​
Field Component

The form.Field component uses Svelte’s snippet syntax and provides:
  • field.state.value - Current field value
  • field.handleChange() - Update field value
  • field.handleBlur() - Mark field as blurred
  • field.state.meta - Field metadata (errors, touched, dirty, etc.)

​
Subscribe Component

The form.Subscribe component lets you subscribe to specific form state to optimize rendering: 
<form.Subscribe
  selector={(state) => ({
    canSubmit: state.canSubmit,
    isSubmitting: state.isSubmitting,
  })}
>
  {#snippet children(state)}
    <button type="submit" disabled={!state.canSubmit}>
      {state.isSubmitting ? '...' : 'Submit'}
    </button>
  {/snippet}
</form.Subscribe>

​
Next Steps

Now that you have a basic form working, explore more advanced features: