# Command Documentation A command menu component that can be used to search, filter, and select items. 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 No results found. Suggestions Introduction Delegation Styling Components Calendar Radio Group Combobox ``` ## Overview The Command component, also known as a command menu, is designed to provide users with a quick and efficient way to search, filter, and select items within an application. It combines the functionality of a search input with a dynamic, filterable list of commands or options, making it ideal for applications that require fast navigation or action execution. ## Key Features - **Dynamic Filtering**: As users type in the input field, the list of commands or items is instantly filtered and sorted based on an (overridable) scoring algorithm. - **Keyboard Navigation**: Full support for keyboard interactions, allowing users to quickly navigate and select items without using a mouse. - **Grouped Commands**: Ability to organize commands into logical groups, enhancing readability and organization. - **Empty and Loading States**: Built-in components to handle scenarios where no results are found or when results are being loaded. - **Accessibility**: Designed with ARIA attributes and keyboard interactions to ensure screen reader compatibility and accessibility standards. ## Architecture The Command component is composed of several sub-components, each with a specific role: - **Root**: The main container that manages the overall state and context of the command menu. - **Input**: The text input field where users can type to search or filter commands. - **List**: The container for the list of commands or items. - **Viewport**: The visible area of the command list, which applies CSS variables to handle dynamic resizing/animations based on the height of the list. - **Empty**: A component to display when no results are found. - **Loading**: A component to display while results are being fetched or processed. - **Group**: A container for a group of items within the command menu. - **GroupHeading**: A header element to provide an accessible label for a group of items. - **GroupItems**: A container for the items within a group. - **Item**: Individual selectable command or item. - **LinkItem**: A variant of `Command.Item` specifically for link-based actions. - **Separator**: A visual separator to divide different sections of the command list. ## Structure Here's an overview of how the Command component is structured in code: ```svelte ``` ## Managing Value State Bits UI offers several approaches to manage and synchronize the Command's value state, catering to different levels of control and integration needs. ### 1. Two-Way Binding For seamless state synchronization, use Svelte's `bind:value` directive. This method automatically keeps your local state in sync with the component's internal state. ```svelte ``` #### Key Benefits - Simplifies state management - Automatically updates `myValue` when the internal state changes (e.g., via clicking on an item) - Allows external control (e.g., selecting an item via a separate button) ### 2. Change Handler To perform additional logic on state changes, use the `onValueChange` prop. This approach is useful when you need to execute side effects when the value changes. ```svelte { // do something with the new value console.log(value); }} > ``` #### Use Cases - Implementing custom behaviors on value change - Integrating with external state management solutions - Triggering side effects (e.g., logging, data fetching) ### 3. 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. You pass a getter function and a setter function to the `bind:value` directive, giving you full control over how the value is updated/retrieved. ```svelte myValue, (newValue) => (myValue = newValue)}> ``` #### When to Use - Implementing complex value change logic - Coordinating multiple UI elements - Debugging state-related issues ##### Note While powerful, fully controlled state should be used judiciously as it increases complexity and can cause unexpected behaviors if not handled carefully. For more in-depth information on controlled components and advanced state management techniques, refer to our [State Management](/docs/state-management) documentation. ## In a Modal You can combine the `Command` component with the `Dialog` component to display the command menu within a modal. ```svelte Open Command Menu J ``` ## Filtering ### Custom Filter By default, the `Command` component uses a scoring algorithm to determine how the items should be sorted/filtered. You can provide a custom filter function to override this behavior. The function should return a number between `0` and `1`, with `1` being a perfect match, and `0` being no match, resulting in the item being hidden entirely. The following example shows how you might implement a strict substring match filter: ```svelte ``` ### Extend Default Filter By default, the `Command` component uses the `computeCommandScore` function to determine the score of each item and filters/sorts them accordingly. This function is exported for you to use and extend as needed. ```svelte ``` ### Disable Filtering You can disable filtering by setting the `shouldFilter` prop to `false`. ```svelte ``` This is useful when you have a lot of custom logic, need to fetch items asynchronously, or just want to handle filtering yourself. You'll be responsible for iterating over the items and determining which ones should be shown. ## Item Selection You can use the `onSelect` prop to handle the selection of items. ```svelte console.log("selected something!")} /> ``` ## Links If you want one of the items to get all the benefits of a link (prefetching, etc.), you should use the `Command.LinkItem` component instead of the `Command.Item` component. The only difference is that the `Command.LinkItem` component will render an `a` element instead of a `div` element. ```svelte ``` ## Imperative API For more advanced use cases, such as custom keybindings, the `Command.Root` component exposes several methods for programmatic control. Access these by binding to the component: ```svelte ``` ### Methods #### `getValidItems()` Returns an array of valid (non-disabled, visible) command items. Useful for checking bounds before operations. ```ts const items = command.getValidItems(); console.log(items.length); // number of selectable items ``` #### `updateSelectedToIndex(index: number)` Sets selection to item at specified index. No-op if index is invalid. ```ts // select third item (if it exists) command.updateSelectedToIndex(2); // with bounds check const items = command.getValidItems(); if (index < items.length) { command.updateSelectedToIndex(index); } ``` #### `updateSelectedByGroup(change: 1 | -1)` Moves selection to first item in next/previous group. Falls back to next/previous item if no group found. ```ts command.updateSelectedByGroup(1); // move to next group command.updateSelectedByGroup(-1); // move to previous group ``` #### `updateSelectedByItem(change: 1 | -1)` Moves selection up/down relative to current item. Wraps around if `loop` option enabled. ```ts command.updateSelectedByItem(1); // next item command.updateSelectedByItem(-1); // previous item ``` ### Usage Example ```svelte { if (e.key === "o") { jumpToLastItem(); } }} /> ``` ## API Reference ### Command.Root The main container that manages the overall state and context of the component. | Property | Type | Description | | -------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `value` $bindable | `string` | The value of the command.`Default: undefined` | | `onValueChange` | `function`- (value: string) => void | A callback that is fired when the command value changes.`Default: undefined` | | `label` | `string` | An accessible label for the command menu. This is not visible and is only used for screen readers.`Default: undefined` | | `filter` | `function`- (value: string, search: string, keywords?: string\[]) => number; | A custom filter function used to filter items. This function should return a number between `0` and `1`, with `1` being a perfect match, and `0` being no match, resulting in the item being hidden entirely. The items are sorted/filtered based on this score.`Default: undefined` | | `shouldFilter` | `boolean` | Whether or not the command menu should filter items. This is useful when you want to apply custom filtering logic outside of the Command component.`Default: true` | | `onStateChange` | `function`- type CommandState = { /\*\* The value of the search query \*/ search: string; /\*\* The value of the selected command menu item \*/ value: string; /\*\* The filtered items \*/ filtered: { /\*\* The count of all visible items. \*/ count: number; /\*\* Map from visible item id to its search store. \*/ items: Map\; /\*\* Set of groups with at least one visible item. \*/ groups: Set\; }; }; type onStateChange = (state: Readonly\) => void; | A callback that fires when the command's internal state changes. This callback receives a readonly snapshot of the current state. The callback is debounced and only fires once per batch of related updates (e.g., when typing triggers filtering and selection changes).`Default: undefined` | | `loop` | `boolean` | Whether or not the command menu should loop through items when navigating with the keyboard.`Default: false` | | `disablePointerSelection` | `boolean` | Set this to true to prevent items from being selected when the users pointer moves over them.`Default: false` | | `vimBindings` | `boolean` | Whether VIM bindings should be enabled or not, which allow the user to navigate using ctrl+n/j/p/k`Default: true` | | `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-command-root` | `''` | Present on the root element. | ### Command.Input The text input field where users can type to search or filter commands. | Property | Type | Description | | -------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `value` $bindable | `string` | The value of the search query. This is used to filter items and to search for items.`Default: undefined` | | `ref` $bindable | `HTMLInputElement` | 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-command-input` | `''` | Present on the input element. | ### Command.List The container for the viewport, items, and other elements of the command menu. | Property | Type | Description | | ------------------------------------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `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-command-list` | `''` | Present on the list element. | | CSS Variable | Description | | --------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `--bits-command-list-height` | The height of the command list element, which is computed by the `Command.Viewport` component. | ### Command.Viewport The visible area of the command list, which applies CSS variables to handle dynamic resizing/animations based on the height of the list. | Property | Type | Description | | ------------------------------------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `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-command-viewport` | `''` | Present on the viewport element. | ### Command.Group A container for a group of items within the command menu. | Property | Type | Description | | --------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `value` | `string` | If a `Command.GroupHeading` is used within this group, the contents of the heading will be used as the value. If the content is dynamic or you wish to have a more specific value, you can provide a unique value for the group here.`Default: undefined` | | `forceMount` | `boolean` | Whether or not the group should always be mounted to the DOM, regardless of the internal filtering logic`Default: false` | | `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-command-group` | `''` | Present on the group element. | ### Command.GroupHeading A heading element to provide an accessible label for a group of items. | Property | Type | Description | | ------------------------------------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `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-command-group-heading` | `''` | Present on the group heading element. | ### Command.GroupItems The container for the items within a group. | Property | Type | Description | | ------------------------------------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `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-command-group-items` | `''` | Present on the group items element. | ### Command.Item Represents a single item within the command menu. If you wish to render an anchor element to link to a page, use the `Command.LinkItem` component. | Property | Type | Description | | ------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `value` required | `string` | The value of the item.`Default: undefined` | | `keywords` | `string[]` | An array of additional keywords or aliases that will be used to filter the item.`Default: undefined` | | `forceMount` | `boolean` | Whether or not the item should always be mounted to the DOM, regardless of the internal filtering logic`Default: false` | | `onSelect` | `function`- () => void | A callback that is fired when the item is selected.`Default: undefined` | | `disabled` | `boolean` | Whether or not the combobox item is disabled. This will prevent interaction/selection.`Default: false` | | `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-disabled` | `''` | Present when the item is disabled. | | `data-selected` | `''` | Present when the item is selected. | | `data-command-item` | `''` | Present on the item element. | ### Command.LinkItem Similar to the `Command.Item` component, but renders an anchor element to take advantage of preloading before navigation. | Property | Type | Description | | ------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `value` required | `string` | The value of the item.`Default: undefined` | | `keywords` | `string[]` | An array of additional keywords or aliases that will be used to filter the item.`Default: undefined` | | `forceMount` | `boolean` | Whether or not the item should always be mounted to the DOM, regardless of the internal filtering logic`Default: false` | | `onSelect` | `function`- () => void | A callback that is fired when the item is selected.`Default: undefined` | | `disabled` | `boolean` | Whether or not the combobox item is disabled. This will prevent interaction/selection.`Default: false` | | `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-disabled` | `''` | Present when the item is disabled. | | `data-selected` | `''` | Present when the item is selected. | | `data-command-item` | `''` | Present on the item element. | ### Command.Empty A component to display when no results are found. | Property | Type | Description | | -------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `forceMount` | `boolean` | Whether or not to forcefully mount the empty state, regardless of the internal filtering logic. Useful when you want to handle filtering yourself.`Default: false` | | `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-command-empty` | `''` | Present on the empty element. | ### Command.Loading A component to display while results are being fetched or processed. | Property | Type | Description | | ------------------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `progress` | `number` | The progress of the loading state.`Default: 0` | | `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-command-loading` | `''` | Present on the loading element. | ### Command.Separator A visual separator to divide different sections of the command list. Visible when the search query is empty or the `forceMount` prop is `true`. | Property | Type | Description | | -------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `forceMount` | `boolean` | Whether or not the separator should always be mounted to the DOM, regardless of the internal filtering logic`Default: false` | | `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-command-separator` | `''` | Present on the separator element. |