feat(Spin): Option to show live output (#303)

* Added live output buffer and option flag

* Update Spin on README.md

* Returned output formatting to previous version.

* Separated the showOutput and liveOutput flags.
Both flags can now be used at once.

* Removed liveOutout flag
showOutput flag is now realtime

* (spin) Consolodated stderr and stdout

* (spin) Consolodated stdout and stderr

* (spin) If being piped, writes to stdout

* Added error check and did some housekeeping

* No longer outputs to tea.View if piped

* Cleaned up the combining of stderr and stdout

* Fixed spinner alignment.  Updated Readme

README.md

@@ -294,6 +294,8 @@ gum pager < README.md
 Display a spinner while running a script or command. The spinner will
 automatically stop after the given command exits.
 
+To view or pipe the command's output, use the `--show-output` flag.
+
 ```bash
 gum spin --spinner dot --title "Buying Bubble Gum..." -- sleep 5
 ```

spin/command.go

@@ -15,14 +15,19 @@ import (
 // Run provides a shell script interface for the spinner bubble.
 // https://github.com/charmbracelet/bubbles/spinner
 func (o Options) Run() error {
+	var isTTY bool
+	info, err := os.Stdout.Stat()
+	isTTY = info.Mode()&os.ModeCharDevice == os.ModeCharDevice
+
 	s := spinner.New()
 	s.Style = o.SpinnerStyle.ToLipgloss()
 	s.Spinner = spinnerMap[o.Spinner]
 	m := model{
-		spinner: s,
-		title:   o.TitleStyle.ToLipgloss().Render(o.Title),
-		command: o.Command,
-		align:   o.Align,
+		spinner:    s,
+		title:      o.TitleStyle.ToLipgloss().Render(o.Title),
+		command:    o.Command,
+		align:      o.Align,
+		showOutput: o.ShowOutput && isTTY,
 	}
 	p := tea.NewProgram(m, tea.WithOutput(os.Stderr))
 	mm, err := p.Run()
@@ -32,15 +37,23 @@ func (o Options) Run() error {
 		return fmt.Errorf("failed to run spin: %w", err)
 	}
 
-	if o.ShowOutput {
-		fmt.Fprint(os.Stdout, m.stdout)
-		fmt.Fprint(os.Stderr, m.stderr)
-	}
-
 	if m.aborted {
 		return exit.ErrAborted
 	}
 
+	if err != nil {
+		return fmt.Errorf("failed to access stdout: %w", err)
+	}
+
+	if o.ShowOutput {
+		if !isTTY {
+			_, err := os.Stdout.WriteString(m.stdout)
+			if err != nil {
+				return fmt.Errorf("failed to write to stdout: %w", err)
+			}
+		}
+	}
+
 	os.Exit(m.status)
 	return nil
 }

spin/options.go

@@ -6,7 +6,7 @@ import "github.com/charmbracelet/gum/style"
 type Options struct {
 	Command []string `arg:"" help:"Command to run"`
 
-	ShowOutput   bool         `help:"Show output of command" default:"false" env:"GUM_SPIN_SHOW_OUTPUT"`
+	ShowOutput   bool         `help:"Show or pipe output of command during execution" default:"false" env:"GUM_SPIN_SHOW_OUTPUT"`
 	Spinner      string       `help:"Spinner type" short:"s" type:"spinner" enum:"line,dot,minidot,jump,pulse,points,globe,moon,monkey,meter,hamburger" default:"dot" env:"GUM_SPIN_SPINNER"`
 	SpinnerStyle style.Styles `embed:"" prefix:"spinner." set:"defaultForeground=212" envprefix:"GUM_SPIN_SPINNER_"`
 	Title        string       `help:"Text to display to user while spinning" default:"Loading..." env:"GUM_SPIN_TITLE"`

spin/spin.go

@@ -20,23 +20,25 @@ import (
 
 	"github.com/charmbracelet/bubbles/spinner"
 	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/lipgloss"
 )
 
 type model struct {
-	spinner spinner.Model
-	title   string
-	align   string
-	command []string
-	aborted bool
-
-	status int
-	stdout string
-	stderr string
+	spinner    spinner.Model
+	title      string
+	align      string
+	command    []string
+	aborted    bool
+	status     int
+	stdout     string
+	showOutput bool
 }
 
+var outbuf strings.Builder
+var errbuf strings.Builder
+
 type finishCommandMsg struct {
 	stdout string
-	stderr string
 	status int
 }
 
@@ -48,7 +50,6 @@ func commandStart(command []string) tea.Cmd {
 		}
 		cmd := exec.Command(command[0], args...) //nolint:gosec
 
-		var outbuf, errbuf strings.Builder
 		cmd.Stdout = &outbuf
 		cmd.Stderr = &errbuf
 
@@ -62,7 +63,6 @@ func commandStart(command []string) tea.Cmd {
 
 		return finishCommandMsg{
 			stdout: outbuf.String(),
-			stderr: errbuf.String(),
 			status: status,
 		}
 	}
@@ -75,11 +75,16 @@ func (m model) Init() tea.Cmd {
 	)
 }
 func (m model) View() string {
+	var header string
 	if m.align == "left" {
-		return m.spinner.View() + " " + m.title
+		header = m.spinner.View() + " " + m.title
+	} else {
+		header = m.title + " " + m.spinner.View()
 	}
-
-	return m.title + " " + m.spinner.View()
+	if !m.showOutput {
+		return header
+	}
+	return lipgloss.JoinVertical(lipgloss.Top, header, errbuf.String(), outbuf.String())
 }
 
 func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
@@ -87,7 +92,6 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	switch msg := msg.(type) {
 	case finishCommandMsg:
 		m.stdout = msg.stdout
-		m.stderr = msg.stderr
 		m.status = msg.status
 		return m, tea.Quit
 	case tea.KeyMsg: