Function useTerminalFocus

cli/src/hooks/use-terminal-focus.ts:69–115

({
  onFocusChange,
  onSupportDetected,
}: UseTerminalFocusOptions)

 * - \x1b[O on focus lost
 */
export function useTerminalFocus({
  onFocusChange,
  onSupportDetected,
}: UseTerminalFocusOptions): void {
  useEffect(() => {
    const stdin = getStdin()
    if (!stdin) {
      return
    }

    let supportDetected = false

    // Enable focus reporting
    enableFocusReporting()

    // Listen for data events on stdin to catch focus in/out sequences
    const handleData = (chunk: Buffer | string) => {
      const data = chunk.toString()

      // Use includes() instead of strict equality to handle cases where
      // terminal batches multiple sequences or keystrokes together
      if (data.includes(FOCUS_IN_EVENT)) {
        // First focus event confirms terminal support
        if (!supportDetected) {
          supportDetected = true
          onSupportDetected?.()
        }
        onFocusChange(true)
      } else if (data.includes(FOCUS_OUT_EVENT)) {
        // First focus event confirms terminal support
        if (!supportDetected) {
          supportDetected = true
          onSupportDetected?.()
        }
        onFocusChange(false)
      }
    }

    stdin.on('data', handleData)

    // Cleanup: disable focus reporting and remove listener
    return () => {
      stdin.off('data', handleData)
      disableFocusReporting()
    }
  }, [onFocusChange, onSupportDetected])
}