Convert remaining examples to Model interface-based structure

examples/fullscreen/main.go

@@ -16,7 +16,7 @@ type model int
 type tickMsg time.Time
 
 func main() {
-	p := tea.NewProgram(initialize, update, view)
+	p := tea.NewProgram(model(5))
 
 	p.EnterAltScreen()
 	err := p.Start()
@@ -27,13 +27,11 @@ func main() {
 	}
 }
 
-func initialize() (tea.Model, tea.Cmd) {
-	return model(5), tick()
+func (m model) Init() tea.Cmd {
+	return tick()
 }
 
-func update(message tea.Msg, mdl tea.Model) (tea.Model, tea.Cmd) {
-	m, _ := mdl.(model)
-
+func (m model) Update(message tea.Msg) (tea.Model, tea.Cmd) {
 	switch msg := message.(type) {
 
 	case tea.KeyMsg:
@@ -58,8 +56,7 @@ func update(message tea.Msg, mdl tea.Model) (tea.Model, tea.Cmd) {
 	return m, nil
 }
 
-func view(mdl tea.Model) string {
-	m, _ := mdl.(model)
+func (m model) View() string {
 	return fmt.Sprintf("\n\n     Hi. This program will exit in %d seconds...", m)
 }
 

examples/http/main.go

@@ -3,7 +3,6 @@ package main
 // A simple program that makes a GET request and prints the response status.
 
 import (
-	"errors"
 	"fmt"
 	"log"
 	"net/http"
@@ -14,31 +13,29 @@ import (
 
 const url = "https://charm.sh/"
 
-type Model struct {
+type model struct {
 	status int
 	err    error
 }
 
 type statusMsg int
-type errMsg error
+
+type errMsg struct{ error }
+
+func (e errMsg) Error() string { return e.Error() }
 
 func main() {
-	p := tea.NewProgram(initialize, update, view)
+	p := tea.NewProgram(model{})
 	if err := p.Start(); err != nil {
 		log.Fatal(err)
 	}
 }
 
-func initialize() (tea.Model, tea.Cmd) {
-	return Model{0, nil}, checkServer
+func (m model) Init() tea.Cmd {
+	return checkServer
 }
 
-func update(msg tea.Msg, model tea.Model) (tea.Model, tea.Cmd) {
-	m, ok := model.(Model)
-	if !ok {
-		return Model{err: errors.New("could not perform assertion on model during update")}, nil
-	}
-
+func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	switch msg := msg.(type) {
 
 	case tea.KeyMsg:
@@ -66,8 +63,7 @@ func update(msg tea.Msg, model tea.Model) (tea.Model, tea.Cmd) {
 	}
 }
 
-func view(model tea.Model) string {
-	m, _ := model.(Model)
+func (m model) View() string {
 	s := fmt.Sprintf("Checking %s...", url)
 	if m.err != nil {
 		s += fmt.Sprintf("something went wrong: %s", m.err)
@@ -83,7 +79,7 @@ func checkServer() tea.Msg {
 	}
 	res, err := c.Get(url)
 	if err != nil {
-		return errMsg(err)
+		return errMsg{err}
 	}
 	return statusMsg(res.StatusCode)
 }

examples/pager/main.go

@@ -53,7 +53,7 @@ func main() {
 		defer f.Close()
 	}
 
-	p := tea.NewProgram(initialize(string(content)), update, view)
+	p := tea.NewProgram(model{content: string(content)})
 
 	// Use the full size of the terminal in its "alternate screen buffer"
 	p.EnterAltScreen()
@@ -75,19 +75,11 @@ type model struct {
 	viewport viewport.Model
 }
 
-func initialize(content string) func() (tea.Model, tea.Cmd) {
-	return func() (tea.Model, tea.Cmd) {
-		return model{
-			// Store content in the model so we can hand it off to the viewport
-			// later.
-			content: content,
-		}, nil
-	}
+func (m model) Init() tea.Cmd {
+	return nil
 }
 
-func update(msg tea.Msg, mdl tea.Model) (tea.Model, tea.Cmd) {
-	m, _ := mdl.(model)
-
+func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	var (
 		cmd  tea.Cmd
 		cmds []tea.Cmd
@@ -142,9 +134,7 @@ func update(msg tea.Msg, mdl tea.Model) (tea.Model, tea.Cmd) {
 	return m, tea.Batch(cmds...)
 }
 
-func view(mdl tea.Model) string {
-	m, _ := mdl.(model)
-
+func (m model) View() string {
 	if !m.ready {
 		return "\n  Initalizing..."
 	}

examples/result/main.go

@@ -29,7 +29,8 @@ func main() {
 
 	// Pass the channel to the initialize function so our Bubble Tea program
 	// can send the final choice along when the time comes.
-	if err := tea.NewProgram(initialize(result), update, view).Start(); err != nil {
+	p := tea.NewProgram(model{cursor: 0, choice: result})
+	if err := p.Start(); err != nil {
 		fmt.Println("Oh no:", err)
 		os.Exit(1)
 	}
@@ -43,15 +44,15 @@ func main() {
 // Pass a channel to the model to listen to the result value. This is a
 // function that returns the initialize function and is typically how you would
 // pass arguments to a tea.Init function.
-func initialize(choice chan string) func() (tea.Model, tea.Cmd) {
-	return func() (tea.Model, tea.Cmd) {
-		return model{cursor: 0, choice: choice}, nil
-	}
+func initialModel(choice chan string) model {
+	return model{cursor: 0, choice: choice}
 }
 
-func update(msg tea.Msg, mdl tea.Model) (tea.Model, tea.Cmd) {
-	m, _ := mdl.(model)
+func (m model) Init() tea.Cmd {
+	return nil
+}
 
+func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	switch msg := msg.(type) {
 	case tea.KeyMsg:
 		switch msg.String() {
@@ -83,9 +84,7 @@ func update(msg tea.Msg, mdl tea.Model) (tea.Model, tea.Cmd) {
 	return m, nil
 }
 
-func view(mdl tea.Model) string {
-	m, _ := mdl.(model)
-
+func (m model) View() string {
 	s := strings.Builder{}
 	s.WriteString("What kind of Bubble Tea would you like to order?\n\n")
 

examples/simple/main.go

@@ -27,10 +27,6 @@ func main() {
 	}
 }
 
-// Messages are events that we respond to in our Update function. This
-// particular one indicates that the timer has ticked.
-type tickMsg time.Time
-
 // A model can be more or less any type of data. It holds all the data for a
 // program, so often it's a struct. For this simple example, however, all
 // we'll need is a simple integer.
@@ -66,6 +62,10 @@ func (m model) View() string {
 	return fmt.Sprintf("Hi. This program will exit in %d seconds. To quit sooner press any key.\n", m)
 }
 
+// Messages are events that we respond to in our Update function. This
+// particular one indicates that the timer has ticked.
+type tickMsg time.Time
+
 func tick() tea.Msg {
 	time.Sleep(time.Second)
 	return tickMsg{}

examples/spinner/main.go

@@ -12,41 +12,35 @@ import (
 	"github.com/muesli/termenv"
 )
 
-var (
-	color = termenv.ColorProfile()
-)
+var term = termenv.ColorProfile()
 
-type Model struct {
+type errMsg error
+
+type model struct {
 	spinner  spinner.Model
 	quitting bool
 	err      error
 }
 
-type errMsg error
-
 func main() {
-	p := tea.NewProgram(initialize, update, view)
+	p := tea.NewProgram(initialModel())
 	if err := p.Start(); err != nil {
 		fmt.Println(err)
 		os.Exit(1)
 	}
 }
 
-func initialize() (tea.Model, tea.Cmd) {
+func initialModel() model {
 	s := spinner.NewModel()
 	s.Frames = spinner.Dot
-
-	return Model{
-		spinner: s,
-	}, spinner.Tick(s)
+	return model{spinner: s}
 }
 
-func update(msg tea.Msg, model tea.Model) (tea.Model, tea.Cmd) {
-	m, ok := model.(Model)
-	if !ok {
-		return model, nil
-	}
+func (m model) Init() tea.Cmd {
+	return spinner.Tick(m.spinner)
+}
 
+func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	switch msg := msg.(type) {
 
 	case tea.KeyMsg:
@@ -74,17 +68,13 @@ func update(msg tea.Msg, model tea.Model) (tea.Model, tea.Cmd) {
 
 }
 
-func view(model tea.Model) string {
-	m, ok := model.(Model)
-	if !ok {
-		return "could not perform assertion on model in view\n"
-	}
+func (m model) View() string {
 	if m.err != nil {
 		return m.err.Error()
 	}
 	s := termenv.
 		String(spinner.View(m.spinner)).
-		Foreground(color.Color("205")).
+		Foreground(term.Color("205")).
 		String()
 	str := fmt.Sprintf("\n\n   %s Loading forever...press q to quit\n\n", s)
 	if m.quitting {

examples/textinput/main.go

@@ -4,7 +4,6 @@ package main
 // component library.
 
 import (
-	"errors"
 	"fmt"
 	"log"
 
@@ -12,48 +11,39 @@ import (
 	tea "github.com/charmbracelet/bubbletea"
 )
 
-type Model struct {
-	textInput input.Model
-	err       error
-}
-
-type tickMsg struct{}
-type errMsg error
-
 func main() {
-	p := tea.NewProgram(
-		initialize,
-		update,
-		view,
-	)
+	p := tea.NewProgram(initialModel())
 
 	if err := p.Start(); err != nil {
 		log.Fatal(err)
 	}
 }
 
-func initialize() (tea.Model, tea.Cmd) {
+type tickMsg struct{}
+type errMsg error
+
+type model struct {
+	textInput input.Model
+	err       error
+}
+
+func initialModel() model {
 	inputModel := input.NewModel()
 	inputModel.Placeholder = "Pikachu"
 	inputModel.Focus()
 
-	return Model{
+	return model{
 		textInput: inputModel,
 		err:       nil,
-	}, input.Blink(inputModel)
+	}
 }
 
-func update(msg tea.Msg, model tea.Model) (tea.Model, tea.Cmd) {
+func (m model) Init() tea.Cmd {
+	return input.Blink(m.textInput)
+}
+
+func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	var cmd tea.Cmd
-	m, ok := model.(Model)
-	if !ok {
-		// When we encounter errors in Update we simply add the error to the
-		// model so we can handle it in the view. We could also return a command
-		// that does something else with the error, like logs it via IO.
-		return Model{
-			err: errors.New("could not perform assertion on model in update"),
-		}, nil
-	}
 
 	switch msg := msg.(type) {
 	case tea.KeyMsg:
@@ -76,13 +66,7 @@ func update(msg tea.Msg, model tea.Model) (tea.Model, tea.Cmd) {
 	return m, cmd
 }
 
-func view(model tea.Model) string {
-	m, ok := model.(Model)
-	if !ok {
-		return "Oh no: could not perform assertion on model."
-	} else if m.err != nil {
-		return fmt.Sprintf("Uh oh: %s", m.err)
-	}
+func (m model) View() string {
 	return fmt.Sprintf(
 		"What’s your favorite Pokémon?\n\n%s\n\n%s",
 		input.View(m.textInput),

examples/textinputs/main.go

@@ -12,9 +12,7 @@ import (
 	te "github.com/muesli/termenv"
 )
 
-const (
-	focusedTextColor = "205"
-)
+const focusedTextColor = "205"
 
 var (
 	color               = te.ColorProfile().Color
@@ -25,11 +23,7 @@ var (
 )
 
 func main() {
-	if err := tea.NewProgram(
-		initialize,
-		update,
-		view,
-	).Start(); err != nil {
+	if err := tea.NewProgram(initialModel()).Start(); err != nil {
 		fmt.Printf("could not start program: %s\n", err)
 		os.Exit(1)
 	}
@@ -43,7 +37,7 @@ type model struct {
 	submitButton  string
 }
 
-func initialize() (tea.Model, tea.Cmd) {
+func initialModel() model {
 	name := input.NewModel()
 	name.Placeholder = "Name"
 	name.Focus()
@@ -58,25 +52,21 @@ func initialize() (tea.Model, tea.Cmd) {
 	email.Placeholder = "Email"
 	email.Prompt = blurredPrompt
 
-	return model{0, name, nickName, email, blurredSubmitButton},
-		tea.Batch(
-			input.Blink(name),
-			input.Blink(nickName),
-			input.Blink(email),
-		)
+	return model{0, name, nickName, email, blurredSubmitButton}
 
 }
+func (m model) Init() tea.Cmd {
+	return tea.Batch(
+		input.Blink(m.nameInput),
+		input.Blink(m.nickNameInput),
+		input.Blink(m.emailInput),
+	)
+}
 
-func update(msg tea.Msg, mdl tea.Model) (tea.Model, tea.Cmd) {
-	m, ok := mdl.(model)
-	if !ok {
-		panic("could not perform assertion on model")
-	}
-
+func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	var cmd tea.Cmd
 
 	switch msg := msg.(type) {
-
 	case tea.KeyMsg:
 		switch msg.String() {
 
@@ -167,12 +157,7 @@ func updateInputs(msg tea.Msg, m model) (model, tea.Cmd) {
 	return m, tea.Batch(cmds...)
 }
 
-func view(mdl tea.Model) string {
-	m, ok := mdl.(model)
-	if !ok {
-		return "could not perform assertion on model"
-	}
-
+func (m model) View() string {
 	s := "\n"
 
 	inputs := []string{
@@ -189,6 +174,5 @@ func view(mdl tea.Model) string {
 	}
 
 	s += "\n\n" + m.submitButton + "\n"
-
 	return s
 }