Command

Q: What is the difference between Command and CommandDialog?

Command renders an inline command menu embedded in the page CommandDialog wraps Command inside a shadcn Dialog for a modal overlay Use CommandDialog for Cmd+K style palettes; use Command for inline comboboxes

Q: What underlying library powers the shadcn Command component?

cmdk by Paco Coursey -- a headless, composable command menu library It provides keyboard navigation (arrow keys, Enter to select) and built-in text filtering

Q: How do you build a combobox (searchable select) using Command?

Wrap Command inside a Popover instead of a Dialog Use PopoverTrigger as the button and PopoverContent containing the Command Close the popover on item selection with setOpen(false)

Q: What does CommandEmpty display and when?

It renders its children when no CommandItem elements match the current search query Useful for "No results found" or "Searching..." messages

Q: Gotcha: Why might filtering not work if a CommandItem only contains an icon?

cmdk filters by the text content of each CommandItem If the item has no visible text, the filter has nothing to match against Fix: add visible text or set the value prop explicitly for custom filtering

Q: What TypeScript type does onSelect expect on a CommandItem?

onSelect takes a callback of type (value: string) => void The value parameter is the lowercased text content or the explicit value prop

shadcn Command component - command palette, search, and keyboard-driven navigation powered by cmdk.

Recipe

Quick-reference recipe card - copy-paste ready.

npx shadcn@latest add command dialog

import {
  Command, CommandDialog, CommandEmpty, CommandGroup,
  CommandInput, CommandItem, CommandList, CommandSeparator,
} from "@/components/ui/command";
 
// Inline command menu
<Command>
  <CommandInput placeholder="Search..." />
  <CommandList>
    <CommandEmpty>No results found.</CommandEmpty>
    <CommandGroup heading="Actions">
      <CommandItem onSelect={() => console.log("new")}>New File</CommandItem>
      <CommandItem onSelect={() => console.log("save")}>Save</CommandItem>
    </CommandGroup>
    <CommandSeparator />
    <CommandGroup heading="Settings">
      <CommandItem>Profile</CommandItem>
      <CommandItem>Preferences</CommandItem>
    </CommandGroup>
  </CommandList>
</Command>

When to reach for this: When you want a keyboard-first search or action palette - Cmd+K style navigation, spotlight search, or combobox selection.

Working Example

"use client";
 
import { useEffect, useState, useCallback } from "react";
import { useRouter } from "next/navigation";
import {
  CommandDialog, CommandEmpty, CommandGroup,
  CommandInput, CommandItem, CommandList, CommandSeparator,
} from "@/components/ui/command";
import {
  FileText, Settings, User, Search, Plus, Moon, Sun, LogOut,
} from "lucide-react";
 
type CommandAction = {
  id: string;
  label: string;
  icon: React.ReactNode;
  shortcut?: string;
  action: () => void;
};
 
export function CommandPalette() {
  const [open, setOpen] = useState(false);
  const router = useRouter();
 
  // Cmd+K to open
  useEffect(() => {
    function onKeyDown(e: KeyboardEvent) {
      if (e.key === "k" && (e.metaKey || e.ctrlKey)) {
        e.preventDefault();
        setOpen((o) => !o);
      }
    }
    document.addEventListener("keydown", onKeyDown);
    return () => document.removeEventListener("keydown", onKeyDown);
  }, []);
 
  const runAndClose = useCallback(
    (fn: () => void) => {
      fn();
      setOpen(false);
    },
    []
  );
 
  const pages: CommandAction[] = [
    { id: "home", label: "Home", icon: <FileText className="mr-2 h-4 w-4" />, action: () => router.push("/") },
    { id: "dashboard", label: "Dashboard", icon: <FileText className="mr-2 h-4 w-4" />, action: () => router.push("/dashboard") },
    { id: "settings", label: "Settings", icon: <Settings className="mr-2 h-4 w-4" />, shortcut: "Cmd+,", action: () => router.push("/settings") },
    { id: "profile", label: "Profile", icon: <User className="mr-2 h-4 w-4" />, action: () => router.push("/profile") },
  ];
 
  const actions: CommandAction[] = [
    { id: "new-doc", label: "New Document", icon: <Plus className="mr-2 h-4 w-4" />, shortcut: "Cmd+N", action: () => console.log("new doc") },
    { id: "search", label: "Search Everything", icon: <Search className="mr-2 h-4 w-4" />, shortcut: "Cmd+F", action: () => console.log("search") },
  ];
 
  const theme: CommandAction[] = [
    { id: "light", label: "Light Mode", icon: <Sun className="mr-2 h-4 w-4" />, action: () => document.documentElement.classList.remove("dark") },
    { id: "dark", label: "Dark Mode", icon: <Moon className="mr-2 h-4 w-4" />, action: () => document.documentElement.classList.add("dark") },
  ];
 
  return (
    <>
      {/* Trigger button */}
      <button
        onClick={() => setOpen(true)}
        className="flex items-center gap-2 rounded-lg border bg-muted/50 px-3 py-1.5 text-sm text-muted-foreground transition-colors hover:bg-muted"
      >
        <Search className="h-4 w-4" />
        <span>Search...</span>
        <kbd className="ml-4 rounded bg-muted px-1.5 py-0.5 text-xs font-mono">Cmd+K</kbd>
      </button>
 
      <CommandDialog open={open} onOpenChange={setOpen}>
        <CommandInput placeholder="Type a command or search..." />
        <CommandList>
          <CommandEmpty>No results found.</CommandEmpty>
 
          <CommandGroup heading="Pages">
            {pages.map((item) => (
              <CommandItem key={item.id} onSelect={() => runAndClose(item.action)}>
                {item.icon}
                <span>{item.label}</span>
                {item.shortcut && (
                  <kbd className="ml-auto text-xs text-muted-foreground">{item.shortcut}</kbd>
                )}
              </CommandItem>
            ))}
          </CommandGroup>
 
          <CommandSeparator />
 
          <CommandGroup heading="Actions">
            {actions.map((item) => (
              <CommandItem key={item.id} onSelect={() => runAndClose(item.action)}>
                {item.icon}
                <span>{item.label}</span>
                {item.shortcut && (
                  <kbd className="ml-auto text-xs text-muted-foreground">{item.shortcut}</kbd>
                )}
              </CommandItem>
            ))}
          </CommandGroup>
 
          <CommandSeparator />
 
          <CommandGroup heading="Theme">
            {theme.map((item) => (
              <CommandItem key={item.id} onSelect={() => runAndClose(item.action)}>
                {item.icon}
                <span>{item.label}</span>
              </CommandItem>
            ))}
          </CommandGroup>
 
          <CommandSeparator />
 
          <CommandGroup heading="Account">
            <CommandItem onSelect={() => runAndClose(() => console.log("logout"))}>
              <LogOut className="mr-2 h-4 w-4" />
              <span>Log out</span>
            </CommandItem>
          </CommandGroup>
        </CommandList>
      </CommandDialog>
    </>
  );
}

What this demonstrates:

Cmd+K keyboard shortcut to open
CommandDialog wrapping (renders in a Dialog)
Grouped commands with icons and keyboard shortcuts
onSelect handlers that navigate or trigger actions
Close-on-select behavior
Search input with automatic filtering

Deep Dive

How It Works

Command is built on cmdk by Paco Coursey - a headless, composable command menu
CommandInput provides a search box that automatically filters CommandItem children by text content
CommandItem is keyboard-navigable - Arrow keys move between items, Enter selects
CommandDialog combines Command with shadcn's Dialog for the modal overlay
CommandGroup provides visual grouping with an optional heading
CommandEmpty renders when no items match the search query
Filtering is client-side by default using the item's text content

Variations

Async search with loading:

function AsyncCommand() {
  const [query, setQuery] = useState("");
  const [results, setResults] = useState<Result[]>([]);
  const [loading, setLoading] = useState(false);
 
  useEffect(() => {
    if (!query) { setResults([]); return; }
    setLoading(true);
    const timer = setTimeout(async () => {
      const data = await fetch(`/api/search?q=${query}`).then((r) => r.json());
      setResults(data);
      setLoading(false);
    }, 300);
    return () => clearTimeout(timer);
  }, [query]);
 
  return (
    <Command shouldFilter={false}>
      <CommandInput value={query} onValueChange={setQuery} />
      <CommandList>
        {loading && <CommandEmpty>Searching...</CommandEmpty>}
        {!loading && results.length === 0 && <CommandEmpty>No results.</CommandEmpty>}
        {results.map((r) => (
          <CommandItem key={r.id} value={r.id} onSelect={() => navigate(r)}>
            {r.title}
          </CommandItem>
        ))}
      </CommandList>
    </Command>
  );
}

Combobox (select with search):

import { Popover, PopoverContent, PopoverTrigger } from "@/components/ui/popover";
 
function Combobox({ options, value, onSelect }: {
  options: { value: string; label: string }[];
  value: string;
  onSelect: (v: string) => void;
}) {
  const [open, setOpen] = useState(false);
 
  return (
    <Popover open={open} onOpenChange={setOpen}>
      <PopoverTrigger asChild>
        <Button variant="outline" role="combobox" aria-expanded={open}>
          {options.find((o) => o.value === value)?.label ?? "Select..."}
        </Button>
      </PopoverTrigger>
      <PopoverContent className="w-[200px] p-0">
        <Command>
          <CommandInput placeholder="Search..." />
          <CommandList>
            <CommandEmpty>No match.</CommandEmpty>
            <CommandGroup>
              {options.map((opt) => (
                <CommandItem key={opt.value} value={opt.value} onSelect={() => { onSelect(opt.value); setOpen(false); }}>
                  {opt.label}
                </CommandItem>
              ))}
            </CommandGroup>
          </CommandList>
        </Command>
      </PopoverContent>
    </Popover>
  );
}

TypeScript Notes

// CommandItem onSelect receives the lowercased value string
<CommandItem
  value="unique-id"
  onSelect={(value: string) => {
    // value is lowercase of the item text or the explicit value prop
  }}
>
 
// Typing command actions
interface CommandAction {
  id: string;
  label: string;
  icon: React.ReactNode;
  shortcut?: string;
  action: () => void;
  keywords?: string[];  // extra search terms
}

Gotchas

onSelect value is lowercased - cmdk lowercases the value for matching. Fix: Use a separate value prop and look up the original data by ID.
shouldFilter={false} for async - If you fetch results from an API, disable the built-in filter. Fix: Set shouldFilter={false} and handle filtering server-side.
Items must have text content - cmdk filters by text content of the CommandItem. If your item only has icons, filtering will not work. Fix: Add visible text or use the value prop for custom filtering.
Dialog z-index - CommandDialog uses the same z-index as Dialog. If you have other overlays, they may conflict. Fix: Adjust the z-index via className on CommandDialog.
Keyboard shortcut conflicts - Cmd+K may conflict with browser or editor shortcuts. Fix: Check for conflicts and document the shortcut for users.

Alternatives

Alternative	Use When	Don't Use When
cmdk (bare)	You want the headless library without shadcn styling	You already use shadcn
Algolia DocSearch	You need full-text search across documentation	You need a general command palette
kbar	You want an alternative command palette with different API	cmdk covers your needs
Native `<datalist>`	You need a simple browser-native autocomplete	You want rich keyboard navigation and grouping

FAQs

What is the difference between `Command` and `CommandDialog`?

Command renders an inline command menu embedded in the page
CommandDialog wraps Command inside a shadcn Dialog for a modal overlay
Use CommandDialog for Cmd+K style palettes; use Command for inline comboboxes

How do you wire up a Cmd+K keyboard shortcut to open the command palette?

useEffect(() => {
  function onKeyDown(e: KeyboardEvent) {
    if (e.key === "k" && (e.metaKey || e.ctrlKey)) {
      e.preventDefault();
      setOpen((o) => !o);
    }
  }
  document.addEventListener("keydown", onKeyDown);
  return () => document.removeEventListener("keydown", onKeyDown);
}, []);

What underlying library powers the shadcn Command component?

cmdk by Paco Coursey -- a headless, composable command menu library
It provides keyboard navigation (arrow keys, Enter to select) and built-in text filtering

Gotcha: Why does `onSelect` return a lowercased value?

cmdk lowercases the value string internally for case-insensitive matching
Fix: use a separate value prop on CommandItem and look up the original data by ID rather than relying on the onSelect string

How do you build a combobox (searchable select) using Command?

Wrap Command inside a Popover instead of a Dialog
Use PopoverTrigger as the button and PopoverContent containing the Command
Close the popover on item selection with setOpen(false)

When should you set `shouldFilter={false}` on Command?

When fetching results from an API (async/server-side search)
The built-in client-side filter would hide results that haven't loaded yet
Handle filtering on the server and pass results directly to CommandItem

How do you implement async search with a debounced API call?

useEffect(() => {
  if (!query) { setResults([]); return; }
  setLoading(true);
  const timer = setTimeout(async () => {
    const data = await fetch(`/api/search?q=${query}`).then(r => r.json());
    setResults(data);
    setLoading(false);
  }, 300);
  return () => clearTimeout(timer);
}, [query]);

What does `CommandEmpty` display and when?

It renders its children when no CommandItem elements match the current search query
Useful for "No results found" or "Searching..." messages

How do you type a command action for use in a dynamic command list?

interface CommandAction {
  id: string;
  label: string;
  icon: React.ReactNode;
  shortcut?: string;
  action: () => void;
  keywords?: string[];
}

Gotcha: Why might filtering not work if a CommandItem only contains an icon?

cmdk filters by the text content of each CommandItem
If the item has no visible text, the filter has nothing to match against
Fix: add visible text or set the value prop explicitly for custom filtering

How do you close the command palette after an item is selected?

const runAndClose = useCallback((fn: () => void) => {
  fn();
  setOpen(false);
}, []);
 
<CommandItem onSelect={() => runAndClose(item.action)}>

What TypeScript type does `onSelect` expect on a CommandItem?

onSelect takes a callback of type (value: string) => void
The value parameter is the lowercased text content or the explicit value prop

Dialog - CommandDialog uses Dialog internally
Button - trigger buttons for the palette
Data Table - filtering UI for tables
Setup - installation

Recipe

Quick-reference recipe card - copy-paste ready.

npx shadcn@latest add command dialog

import {
  Command, CommandDialog, CommandEmpty, CommandGroup,
  CommandInput, CommandItem, CommandList, CommandSeparator,
} from "@/components/ui/command";
 
// Inline command menu
<Command>
  <CommandInput placeholder="Search..." />
  <CommandList>
    <CommandEmpty>No results found.</CommandEmpty>
    <CommandGroup heading="Actions">
      <CommandItem onSelect={() => console.log("new")}>New File</CommandItem>
      <CommandItem onSelect={() => console.log("save")}>Save</CommandItem>
    </CommandGroup>
    <CommandSeparator />
    <CommandGroup heading="Settings">
      <CommandItem>Profile</CommandItem>
      <CommandItem>Preferences</CommandItem>
    </CommandGroup>
  </CommandList>
</Command>

When to reach for this: When you want a keyboard-first search or action palette - Cmd+K style navigation, spotlight search, or combobox selection.

Working Example

"use client";
 
import { useEffect, useState, useCallback } from "react";
import { useRouter } from "next/navigation";
import {
  CommandDialog, CommandEmpty, CommandGroup,
  CommandInput, CommandItem, CommandList, CommandSeparator,
} from "@/components/ui/command";
import {
  FileText, Settings, User, Search, Plus, Moon, Sun, LogOut,
} from "lucide-react";
 
type CommandAction = {
  id: string;
  label: string;
  icon: React.ReactNode;
  shortcut?: string;
  action: () => void;
};
 
export function CommandPalette() {
  const [open, setOpen] = useState(false);
  const router = useRouter();
 
  // Cmd+K to open
  useEffect(() => {
    function onKeyDown(e: KeyboardEvent) {
      if (e.key === "k" && (e.metaKey || e.ctrlKey)) {
        e.preventDefault();
        setOpen((o) => !o);
      }
    }
    document.addEventListener("keydown", onKeyDown);
    return () => document.removeEventListener("keydown", onKeyDown);
  }, []);
 
  const runAndClose = useCallback(
    (fn: () => void) => {
      fn();
      setOpen(false);
    },
    []
  );
 
  const pages: CommandAction[] = [
    { id: "home", label: "Home", icon: <FileText className="mr-2 h-4 w-4" />, action: () => router.push("/") },
    { id: "dashboard", label: "Dashboard", icon: <FileText className="mr-2 h-4 w-4" />, action: () => router.push("/dashboard") },
    { id: "settings", label: "Settings", icon: <Settings className="mr-2 h-4 w-4" />, shortcut: "Cmd+,", action: () => router.push("/settings") },
    { id: "profile", label: "Profile", icon: <User className="mr-2 h-4 w-4" />, action: () => router.push("/profile") },
  ];
 
  const actions: CommandAction[] = [
    { id: "new-doc", label: "New Document", icon: <Plus className="mr-2 h-4 w-4" />, shortcut: "Cmd+N", action: () => console.log("new doc") },
    { id: "search", label: "Search Everything", icon: <Search className="mr-2 h-4 w-4" />, shortcut: "Cmd+F", action: () => console.log("search") },
  ];
 
  const theme: CommandAction[] = [
    { id: "light", label: "Light Mode", icon: <Sun className="mr-2 h-4 w-4" />, action: () => document.documentElement.classList.remove("dark") },
    { id: "dark", label: "Dark Mode", icon: <Moon className="mr-2 h-4 w-4" />, action: () => document.documentElement.classList.add("dark") },
  ];
 
  return (
    <>
      {/* Trigger button */}
      <button
        onClick={() => setOpen(true)}
        className="flex items-center gap-2 rounded-lg border bg-muted/50 px-3 py-1.5 text-sm text-muted-foreground transition-colors hover:bg-muted"
      >
        <Search className="h-4 w-4" />
        <span>Search...</span>
        <kbd className="ml-4 rounded bg-muted px-1.5 py-0.5 text-xs font-mono">Cmd+K</kbd>
      </button>
 
      <CommandDialog open={open} onOpenChange={setOpen}>
        <CommandInput placeholder="Type a command or search..." />
        <CommandList>
          <CommandEmpty>No results found.</CommandEmpty>
 
          <CommandGroup heading="Pages">
            {pages.map((item) => (
              <CommandItem key={item.id} onSelect={() => runAndClose(item.action)}>
                {item.icon}
                <span>{item.label}</span>
                {item.shortcut && (
                  <kbd className="ml-auto text-xs text-muted-foreground">{item.shortcut}</kbd>
                )}
              </CommandItem>
            ))}
          </CommandGroup>
 
          <CommandSeparator />
 
          <CommandGroup heading="Actions">
            {actions.map((item) => (
              <CommandItem key={item.id} onSelect={() => runAndClose(item.action)}>
                {item.icon}
                <span>{item.label}</span>
                {item.shortcut && (
                  <kbd className="ml-auto text-xs text-muted-foreground">{item.shortcut}</kbd>
                )}
              </CommandItem>
            ))}
          </CommandGroup>
 
          <CommandSeparator />
 
          <CommandGroup heading="Theme">
            {theme.map((item) => (
              <CommandItem key={item.id} onSelect={() => runAndClose(item.action)}>
                {item.icon}
                <span>{item.label}</span>
              </CommandItem>
            ))}
          </CommandGroup>
 
          <CommandSeparator />
 
          <CommandGroup heading="Account">
            <CommandItem onSelect={() => runAndClose(() => console.log("logout"))}>
              <LogOut className="mr-2 h-4 w-4" />
              <span>Log out</span>
            </CommandItem>
          </CommandGroup>
        </CommandList>
      </CommandDialog>
    </>
  );
}

What this demonstrates:

Cmd+K keyboard shortcut to open
CommandDialog wrapping (renders in a Dialog)
Grouped commands with icons and keyboard shortcuts
onSelect handlers that navigate or trigger actions
Close-on-select behavior
Search input with automatic filtering

Deep Dive

How It Works

Command is built on cmdk by Paco Coursey - a headless, composable command menu
CommandInput provides a search box that automatically filters CommandItem children by text content
CommandItem is keyboard-navigable - Arrow keys move between items, Enter selects
CommandDialog combines Command with shadcn's Dialog for the modal overlay
CommandGroup provides visual grouping with an optional heading
CommandEmpty renders when no items match the search query
Filtering is client-side by default using the item's text content

Variations

Async search with loading:

function AsyncCommand() {
  const [query, setQuery] = useState("");
  const [results, setResults] = useState<Result[]>([]);
  const [loading, setLoading] = useState(false);
 
  useEffect(() => {
    if (!query) { setResults([]); return; }
    setLoading(true);
    const timer = setTimeout(async () => {
      const data = await fetch(`/api/search?q=${query}`).then((r) => r.json());
      setResults(data);
      setLoading(false);
    }, 300);
    return () => clearTimeout(timer);
  }, [query]);
 
  return (
    <Command shouldFilter={false}>
      <CommandInput value={query} onValueChange={setQuery} />
      <CommandList>
        {loading && <CommandEmpty>Searching...</CommandEmpty>}
        {!loading && results.length === 0 && <CommandEmpty>No results.</CommandEmpty>}
        {results.map((r) => (
          <CommandItem key={r.id} value={r.id} onSelect={() => navigate(r)}>
            {r.title}
          </CommandItem>
        ))}
      </CommandList>
    </Command>
  );
}

Combobox (select with search):

import { Popover, PopoverContent, PopoverTrigger } from "@/components/ui/popover";
 
function Combobox({ options, value, onSelect }: {
  options: { value: string; label: string }[];
  value: string;
  onSelect: (v: string) => void;
}) {
  const [open, setOpen] = useState(false);
 
  return (
    <Popover open={open} onOpenChange={setOpen}>
      <PopoverTrigger asChild>
        <Button variant="outline" role="combobox" aria-expanded={open}>
          {options.find((o) => o.value === value)?.label ?? "Select..."}
        </Button>
      </PopoverTrigger>
      <PopoverContent className="w-[200px] p-0">
        <Command>
          <CommandInput placeholder="Search..." />
          <CommandList>
            <CommandEmpty>No match.</CommandEmpty>
            <CommandGroup>
              {options.map((opt) => (
                <CommandItem key={opt.value} value={opt.value} onSelect={() => { onSelect(opt.value); setOpen(false); }}>
                  {opt.label}
                </CommandItem>
              ))}
            </CommandGroup>
          </CommandList>
        </Command>
      </PopoverContent>
    </Popover>
  );
}

TypeScript Notes

// CommandItem onSelect receives the lowercased value string
<CommandItem
  value="unique-id"
  onSelect={(value: string) => {
    // value is lowercase of the item text or the explicit value prop
  }}
>
 
// Typing command actions
interface CommandAction {
  id: string;
  label: string;
  icon: React.ReactNode;
  shortcut?: string;
  action: () => void;
  keywords?: string[];  // extra search terms
}

Gotchas

onSelect value is lowercased - cmdk lowercases the value for matching. Fix: Use a separate value prop and look up the original data by ID.
shouldFilter={false} for async - If you fetch results from an API, disable the built-in filter. Fix: Set shouldFilter={false} and handle filtering server-side.
Items must have text content - cmdk filters by text content of the CommandItem. If your item only has icons, filtering will not work. Fix: Add visible text or use the value prop for custom filtering.
Dialog z-index - CommandDialog uses the same z-index as Dialog. If you have other overlays, they may conflict. Fix: Adjust the z-index via className on CommandDialog.
Keyboard shortcut conflicts - Cmd+K may conflict with browser or editor shortcuts. Fix: Check for conflicts and document the shortcut for users.

Alternatives

Alternative	Use When	Don't Use When
cmdk (bare)	You want the headless library without shadcn styling	You already use shadcn
Algolia DocSearch	You need full-text search across documentation	You need a general command palette
kbar	You want an alternative command palette with different API	cmdk covers your needs
Native `<datalist>`	You need a simple browser-native autocomplete	You want rich keyboard navigation and grouping

FAQs

What is the difference between `Command` and `CommandDialog`?

Command renders an inline command menu embedded in the page
CommandDialog wraps Command inside a shadcn Dialog for a modal overlay
Use CommandDialog for Cmd+K style palettes; use Command for inline comboboxes

How do you wire up a Cmd+K keyboard shortcut to open the command palette?

useEffect(() => {
  function onKeyDown(e: KeyboardEvent) {
    if (e.key === "k" && (e.metaKey || e.ctrlKey)) {
      e.preventDefault();
      setOpen((o) => !o);
    }
  }
  document.addEventListener("keydown", onKeyDown);
  return () => document.removeEventListener("keydown", onKeyDown);
}, []);

What underlying library powers the shadcn Command component?

cmdk by Paco Coursey -- a headless, composable command menu library
It provides keyboard navigation (arrow keys, Enter to select) and built-in text filtering

Gotcha: Why does `onSelect` return a lowercased value?

cmdk lowercases the value string internally for case-insensitive matching
Fix: use a separate value prop on CommandItem and look up the original data by ID rather than relying on the onSelect string

How do you build a combobox (searchable select) using Command?

Wrap Command inside a Popover instead of a Dialog
Use PopoverTrigger as the button and PopoverContent containing the Command
Close the popover on item selection with setOpen(false)

When should you set `shouldFilter={false}` on Command?

When fetching results from an API (async/server-side search)
The built-in client-side filter would hide results that haven't loaded yet
Handle filtering on the server and pass results directly to CommandItem

How do you implement async search with a debounced API call?

useEffect(() => {
  if (!query) { setResults([]); return; }
  setLoading(true);
  const timer = setTimeout(async () => {
    const data = await fetch(`/api/search?q=${query}`).then(r => r.json());
    setResults(data);
    setLoading(false);
  }, 300);
  return () => clearTimeout(timer);
}, [query]);

What does `CommandEmpty` display and when?

It renders its children when no CommandItem elements match the current search query
Useful for "No results found" or "Searching..." messages

How do you type a command action for use in a dynamic command list?

interface CommandAction {
  id: string;
  label: string;
  icon: React.ReactNode;
  shortcut?: string;
  action: () => void;
  keywords?: string[];
}

Gotcha: Why might filtering not work if a CommandItem only contains an icon?

cmdk filters by the text content of each CommandItem
If the item has no visible text, the filter has nothing to match against
Fix: add visible text or set the value prop explicitly for custom filtering

How do you close the command palette after an item is selected?

const runAndClose = useCallback((fn: () => void) => {
  fn();
  setOpen(false);
}, []);
 
<CommandItem onSelect={() => runAndClose(item.action)}>

What TypeScript type does `onSelect` expect on a CommandItem?

onSelect takes a callback of type (value: string) => void
The value parameter is the lowercased text content or the explicit value prop

Dialog - CommandDialog uses Dialog internally
Button - trigger buttons for the palette
Data Table - filtering UI for tables
Setup - installation

Command

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