bubbletea/examples/textinput/main.go

package main

import (
	"errors"
	"fmt"
	"log"

	tea "github.com/charmbracelet/bubbletea"
	input "github.com/charmbracelet/bubbletea/textinput"
)

type Model struct {
	textInput input.Model
	err       error
}

type tickMsg struct{}
type errMsg error

func main() {
	p := tea.NewProgram(
		initialize,
		update,
		view,
	)

	if err := p.Start(); err != nil {
		log.Fatal(err)
	}
}

func initialize() (tea.Model, tea.Cmd) {
	inputModel := input.NewModel()
	inputModel.Placeholder = "Pikachu"
	inputModel.Focus()

	return Model{
		textInput: inputModel,
		err:       nil,
	}, input.Blink(inputModel)
}

func update(msg tea.Msg, model tea.Model) (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:
		switch msg.Type {
		case tea.KeyCtrlC:
			fallthrough
		case tea.KeyEsc:
			fallthrough
		case tea.KeyEnter:
			return m, tea.Quit
		}

	// We handle errors just like any other message
	case errMsg:
		m.err = msg
		return m, nil
	}

	m.textInput, cmd = input.Update(msg, m.textInput)
	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)
	}
	return fmt.Sprintf(
		"What’s your favorite Pokémon?\n\n%s\n\n%s",
		input.View(m.textInput),
		"(esc to quit)",
	) + "\n"
}