Implementing Command Palettes

Overview

Command palettes (Cmd+K / Ctrl+K) need precise keyboard navigation, scroll behavior, and stable references to avoid re-render loops. This skill covers the mechanical patterns that make command palettes feel responsive.

When to Use

• Building a Cmd+K command palette in React
• Implementing arrow key navigation with visual selection
• Keeping selected items visible during keyboard navigation
• Filtering commands by label text AND keyboard shortcuts
• Experiencing infinite re-renders when commands update

Quick Reference

Feature	Implementation
Arrow navigation	Track selectedIndex, clamp with Math.min/max
Keep in view	scrollIntoView({ block: 'nearest', behavior: 'smooth' })
Shortcut matching	Strip spaces from shortcuts, match against query
Stable icons	Define icon elements outside component
Stable handlers	useCallback + noop constant for disabled states

Keyboard Navigation

Index Management

const [selectedIndex, setSelectedIndex] = useState(0);

useEffect(() => {
  if (!isOpen) return;

  const handleKeyDown = (e: KeyboardEvent) => {
    switch (e.key) {
      case 'ArrowDown':
        e.preventDefault();
        // Clamp to last item
        setSelectedIndex((prev) => Math.min(prev + 1, filteredItems.length - 1));
        break;
      case 'ArrowUp':
        e.preventDefault();
        // Clamp to first item
        setSelectedIndex((prev) => Math.max(prev - 1, 0));
        break;
      case 'Enter':
        e.preventDefault();
        if (filteredItems[selectedIndex]) {
          executeCommand(filteredItems[selectedIndex]);
          close();
        }
        break;
      case 'Escape':
        e.preventDefault();
        close();
        break;
    }
  };