Spinner example

examples/spinner/main.go

@@ -0,0 +1,85 @@
+package main
+
+import (
+	"fmt"
+	"log"
+
+	"github.com/charmbracelet/tea"
+	"github.com/charmbracelet/teaparty/spinner"
+	"github.com/muesli/termenv"
+)
+
+var (
+	color = termenv.ColorProfile()
+)
+
+type Model struct {
+	spinner spinner.Model
+}
+
+func main() {
+	p := tea.NewProgram(initialize, update, view, subscriptions)
+	if err := p.Start(); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func initialize() (tea.Model, tea.Cmd) {
+	m := spinner.NewModel()
+	m.Type = spinner.Dot
+
+	return Model{
+		spinner: m,
+	}, nil
+}
+
+func update(msg tea.Msg, model tea.Model) (tea.Model, tea.Cmd) {
+	m, ok := model.(Model)
+	if !ok {
+		return model, nil
+	}
+
+	switch msg := msg.(type) {
+
+	case tea.KeyMsg:
+		switch msg.String() {
+		case "q":
+			fallthrough
+		case "esc":
+			fallthrough
+		case "ctrl+c":
+			return m, tea.Quit
+		default:
+			return m, nil
+		}
+
+	default:
+		m.spinner, _ = spinner.Update(msg, m.spinner)
+		return m, nil
+	}
+
+}
+
+func view(model tea.Model) string {
+	m, ok := model.(Model)
+	if !ok {
+		return tea.ModelAssertionErr.String()
+	}
+	s := termenv.
+		String(spinner.View(m.spinner)).
+		Foreground(color.Color("205")).
+		String()
+	return fmt.Sprintf("\n\n   %s Loading forever...press q to quit\n\n", s)
+}
+
+func subscriptions(_ tea.Model) tea.Subs {
+	return tea.Subs{
+		"tick": func(model tea.Model) tea.Msg {
+			m, ok := model.(Model)
+			if !ok {
+				return tea.ModelAssertionErr
+			}
+			return spinner.Sub(m.spinner)
+		},
+	}
+}

tea.go

@@ -93,6 +93,9 @@ func NewErrMsgFromErr(e error) ErrMsg {
 	return ErrMsg{e}
 }
 
+// ModelAssertionErr can be used when a model assertion didn't go as planned
+var ModelAssertionErr = NewErrMsg("could not perform assertion on model")
+
 // Quit is a command that tells the program to exit
 func Quit(_ Model) Msg {
 	return quitMsg{}