# Date Field Documentation
Enables users to input specific dates within a designated field.
This is a documentation section that potentially contains examples, demos, and other useful information related to a specific part of Bits UI. When helping users with this documentation, you can ignore the classnames applied to the demos unless they are relevant to the user's issue.
```svelte
Birthday
{#snippet children({ segments })}
{#each segments as { part, value }}
{#if part === "literal"}
{value}
{:else}
{value}
{/if}
{/each}
{/snippet}
```
##### Heads up!
Before diving into this component, it's important to understand how dates/times work in Bits UI. Please read the [Dates](/docs/dates) documentation to learn more!
## Overview
The `DateField` component is an alternative to the native `` element. It provides a more flexible and customizable way to select dates within a designated field.
## Structure
```svelte
Check-in date
{#snippet children({ segments })}
{#each segments as { part, value }}
{value}
{/each}
{/snippet}
```
## Reusable Components
It's recommended to use the `DateField` primitives to build your own custom date field component that can be used throughout your application.
The following example shows how you might create a reusable `MyDateField` component that can be used throughout your application. For style inspiration, reference the featured demo at the top of this page.
MyDateField.svelte
```svelte
{labelText}
{#snippet children({ segments })}
{#each segments as { part, value }}
{value}
{/each}
{/snippet}
```
```svelte
{labelText}
{#snippet children({ segments })}
{#each segments as { part, value }}
{#if part === "literal"}
{value}
{:else}
{value}
{/if}
{/each}
{/snippet}
```
We'll be using this newly created `MyDateField` component in the following demos and examples to prevent repeating the same code, so be sure to reference it as you go through the documentation.
## Segments
A segment of the `DateField` represents a not only a specific part of the date, such as the day, month, year, hour, but can also reference a `"literal"` which is typically a separator between the different parts of the date, and varies based on the `locale`.
Notice that in the `MyDateField` component we created, we're styling the `DateField.Segment` components differently based on whether they are a `"literal"` or not.
## Placeholder
The `placeholder` prop for the `DateField.Root` component isn't what is displayed when the field is empty, but rather what date our field should start with when the user attempts to cycle through the segments. The placeholder can also be used to set a granularity for the date field, which will determine which type of `DateValue` object is used for the `value`.
By default, the `placeholder` will be set to the current date, and be of type `CalendarDate`. However, if we wanted this date field to also allow for selecting a time, we could set the placeholder to a `CalendarDateTime` object.
```svelte
```
If we're collecting a date from the user where we want the timezone as well, we can use a `ZonedDateTime` object instead.
```svelte
```
##### Leap Years!
If you're creating a date field for something like a birthday, ensure your placeholder is set in a leap year to ensure users born on a leap year will be able to select the correct date.
## Managing Placeholder State
This section covers how to manage the `placeholder` state of the Date Field.
### Two-Way Binding
Use `bind:placeholder` for simple, automatic state synchronization:
```svelte
```
### Fully Controlled
Use a [Function Binding](https://svelte.dev/docs/svelte/bind#Function-bindings) for complete control over the state's reads and writes.
```svelte
```
## Managing Value State
This section covers how to manage the `value` state of the Date Field.
### Two-Way Binding
Use `bind:value` for simple, automatic state synchronization:
```svelte
```
### Fully Controlled
For complete control over the component's state, use a [Function Binding](https://svelte.dev/docs/svelte/bind#Function-bindings) to manage the value state externally.
```svelte
```
## Default Value
Often, you'll want to start the `DateField.Root` component with a default value. Likely this value will come from a database in the format of an ISO 8601 string. You can use the `parseDate` function from the `@internationalized/date` package to parse the string into a `CalendarDate` object.
+page.svelte
```svelte
```
Now our input is populated with the default value. In addition to the `parseDate` function, you can also use `parseDateTime` or `parseZonedDateTime` to parse the string into a `CalendarDateTime` or `ZonedDateTime` object respectively.
## Validation
### Minimum Value
You can set a minimum value for the `DateField.Root` component by using the `minValue` prop. If a user selects a date that is less than the minimum value, the date field will be marked as invalid.
```svelte
```
In the example above, we're setting the minimum value to today, and the default value to yesterday. This causes the date field to be marked as invalid, and we can style it accordingly. If you adjust the date to be greater than the minimum value, the invalid state will be cleared.
### Maximum Value
You can set a maximum value for the `DateField.Root` component by using the `maxValue` prop. If a user selects a date that is greater than the maximum value, the date field will be marked as invalid.
```svelte
```
In the example above, we're setting the maximum value to today, and the default value to tomorrow. This causes the date field to be marked as invalid, and we can style it accordingly. If you adjust the date to be less than the maximum value, the invalid state will be cleared.
### Custom Validation
You can use the `validate` prop to provide a custom validation function for the date field. This function should return a string or array of strings as validation errors if the date is invalid, or undefined/nothing if the date is valid.
The strings are then passed to the `onInvalid` callback, which you can use to display an error message to the user.
```svelte
```
In the example above, we're setting the `isDateUnavailable` prop to a function that returns `true` for the first day of the month. Try selecting a date that is the first day of the month to see the date field marked as invalid.
## Granularity
The `granularity` prop sets the granularity of the date field, which determines which segments are rendered in the date field. The `granularity` can be set to either `'day'`, `'hour'`, `'minute'`, or `'second'`.
```svelte
```
In the example above, we're setting the granularity to `'second'`, which means that the date field will include an additional segment for the seconds.
## Localization
You can use the `locale` prop to set the locale of the date field. This will affect the formatting of the date field's segments and placeholders.
```svelte
```
## API Reference
### DateField.Root
The root date field component.
| Property | Type | Description |
| -------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `value` $bindable | `DateValue`- import type { CalendarDate, CalendarDateTime, ZonedDateTime } from "@internationalized/date"; type DateValue = CalendarDate \| CalendarDateTime \| ZonedDateTime | The selected date.`Default: undefined` |
| `onValueChange` | `function`- (value: DateValue) => void | A function that is called when the selected date changes.`Default: undefined` |
| `placeholder` $bindable | `DateValue`- import type { CalendarDate, CalendarDateTime, ZonedDateTime } from "@internationalized/date"; type DateValue = CalendarDate \| CalendarDateTime \| ZonedDateTime | The placeholder date, which is used to determine what date to start the segments from when no value exists.`Default: undefined` |
| `onPlaceholderChange` | `function`- (value: DateValue) => void | A function that is called when the placeholder date changes.`Default: undefined` |
| `required` | `boolean` | Whether or not the date field is required.`Default: false` |
| `validate` | `function`- (value: DateValue) => boolean | A function that returns whether or not a date is unavailable.`Default: undefined` |
| `onInvalid` | `function`- (value: DateValue) => void | A callback fired when the date field's value is invalid.`Default: undefined` |
| `errorMessageId` | `string` | The `id` of the element which contains the error messages for the date field when the date is invalid.`Default: undefined` |
| `hourCycle` | `enum`- '12' \| '24' | The hour cycle to use for formatting times. Defaults to the locale preference`Default: undefined` |
| `granularity` | `enum`- 'day' \| 'hour' \| 'minute' \| 'second' | The granularity to use for formatting the field. Defaults to `'day'` if a `CalendarDate` is provided, otherwise defaults to `'minute'`. The field will render segments for each part of the date up to and including the specified granularity.`Default: undefined` |
| `hideTimeZone` | `boolean` | Whether or not to hide the time zone segment of the field.`Default: false` |
| `maxValue` | `DateValue`- import type { CalendarDate, CalendarDateTime, ZonedDateTime } from "@internationalized/date"; type DateValue = CalendarDate \| CalendarDateTime \| ZonedDateTime | The maximum valid date that can be entered.`Default: undefined` |
| `minValue` | `DateValue`- import type { CalendarDate, CalendarDateTime, ZonedDateTime } from "@internationalized/date"; type DateValue = CalendarDate \| CalendarDateTime \| ZonedDateTime | The minimum valid date that can be entered.`Default: undefined` |
| `locale` | `string` | The locale to use for formatting dates.`Default: 'en-US'` |
| `disabled` | `boolean` | Whether or not the accordion is disabled.`Default: false` |
| `readonly` | `boolean` | Whether or not the field is readonly.`Default: false` |
| `readonlySegments` | `EditableSegmentPart[]`- "day" \| "month" \| "year" \| "hour" \| "minute" \| "second" \| "dayPeriod" | An array of segments that should be readonly, which prevent user input on them.`Default: undefined` |
| `children` | `Snippet` | The children content to render.`Default: undefined` |
### DateField.Input
The container for the segments of the date field.
| Property | Type | Description |
| -------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `name` | `string` | The name of the date field used for form submission. If provided, a hidden input element will be rendered alongside the date field.`Default: undefined` |
| `ref` $bindable | `HTMLDivElement` | The underlying DOM element being rendered. You can bind to this to get a reference to the element.`Default: undefined` |
| `children` | `Snippet`- Snippet | The children content to render.`Default: undefined` |
| `child` | `Snippet`- type SnippetProps = { props: Record\; }; | Use render delegation to render your own element. See [Child Snippet](/docs/child-snippet) docs for more information.`Default: undefined` | | Data Attribute | Value | Description |
| ------------------------------------------------------------------------------- | ----------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------ |
| `data-invalid` | `''` | Present on the element when the field is invalid. |
| `data-disabled` | `''` | Present on the element when the field is disabled. |
| `data-date-field-input` | `''` | Present on the element. |
### DateField.Segment
A segment of the date field.
| Property | Type | Description |
| ------------------------------------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `part` required | `SegmentPart`- "month" \| "day" \| "year" \| "hour" \| "minute" \| "second" \| "dayPeriod" \| "timeZoneName" \| "literal"; | The part of the date to render.`Default: undefined` |
| `ref` $bindable | `HTMLDivElement` | The underlying DOM element being rendered. You can bind to this to get a reference to the element.`Default: undefined` |
| `children` | `Snippet` | The children content to render.`Default: undefined` |
| `child` | `Snippet`- type SnippetProps = { props: Record\; }; | Use render delegation to render your own element. See [Child Snippet](/docs/child-snippet) docs for more information.`Default: undefined` | | Data Attribute | Value | Description |
| ------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------ |
| `data-invalid` | `''` | Present on the element when the field is invalid |
| `data-disabled` | `''` | Present on the element when the field is disabled |
| `data-readonly` | `''` | Present on the element when the field or segment is readonly |
| `data-segment` | `enum` | The part of the date to render. |
| `data-date-field-segment` | `''` | Present on the element. |
### DateField.Label
The label for the date field.
| Property | Type | Description |
| ------------------------------------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `ref` $bindable | `HTMLSpanElement` | The underlying DOM element being rendered. You can bind to this to get a reference to the element.`Default: undefined` |
| `children` | `Snippet` | The children content to render.`Default: undefined` |
| `child` | `Snippet`- type SnippetProps = { props: Record\; }; | Use render delegation to render your own element. See [Child Snippet](/docs/child-snippet) docs for more information.`Default: undefined` | | Data Attribute | Value | Description |
| ------------------------------------------------------------------------------- | ----------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------ |
| `data-invalid` | `''` | Present on the element when the field is invalid |
| `data-disabled` | `''` | Present on the element when the field is disabled |
| `data-date-field-label` | `''` | Present on the element. |