doc: Add textarea examples (#357)

* chore: bump bubbles@master

* doc(textarea): Add example of `chat` application with textarea

* doc(textarea): Add example of `textarea` prompting the user to tell a story

* doc(textarea): Add example of `split-editors` on how to manage multiple textareas

examples/chat/main.go

@@ -0,0 +1,110 @@
+package main
+
+// A simple program demonstrating the text area component from the Bubbles
+// component library.
+
+import (
+	"fmt"
+	"log"
+	"strings"
+
+	"github.com/charmbracelet/bubbles/textarea"
+	"github.com/charmbracelet/bubbles/viewport"
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/lipgloss"
+)
+
+func main() {
+	p := tea.NewProgram(initialModel())
+
+	if err := p.Start(); err != nil {
+		log.Fatal(err)
+	}
+}
+
+type tickMsg struct{}
+type errMsg error
+
+type model struct {
+	viewport    viewport.Model
+	messages    []string
+	textarea    textarea.Model
+	senderStyle lipgloss.Style
+	err         error
+}
+
+func initialModel() model {
+	ta := textarea.New()
+	ta.Placeholder = "Send a message..."
+	ta.Focus()
+
+	ta.Prompt = "┃ "
+	ta.CharLimit = 280
+
+	ta.SetWidth(30)
+	ta.SetHeight(3)
+
+	// Remove cursor line styling
+	ta.FocusedStyle.CursorLine = lipgloss.NewStyle()
+
+	ta.ShowLineNumbers = false
+
+	vp := viewport.New(30, 10)
+	vp.SetContent(`Welcome to the Bubbles multi-line text input!
+Try typing any message and pressing ENTER.
+If you write a long message, it will automatically wrap :D
+	`)
+
+	ta.KeyMap.InsertNewline.SetEnabled(false)
+
+	return model{
+		textarea:    ta,
+		messages:    []string{},
+		viewport:    vp,
+		senderStyle: lipgloss.NewStyle().Foreground(lipgloss.Color("5")),
+		err:         nil,
+	}
+}
+
+func (m model) Init() tea.Cmd {
+	return textarea.Blink
+}
+
+func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+	var (
+		tiCmd tea.Cmd
+		vpCmd tea.Cmd
+	)
+
+	m.textarea, tiCmd = m.textarea.Update(msg)
+	m.viewport, vpCmd = m.viewport.Update(msg)
+
+	switch msg := msg.(type) {
+	case tea.KeyMsg:
+		switch msg.Type {
+		case tea.KeyCtrlC, tea.KeyEsc:
+			fmt.Println(m.textarea.Value())
+			return m, tea.Quit
+		case tea.KeyEnter:
+			m.messages = append(m.messages, m.senderStyle.Render("You: ")+m.textarea.Value())
+			m.viewport.SetContent(strings.Join(m.messages, "\n"))
+			m.textarea.Reset()
+			m.viewport.GotoBottom()
+		}
+
+	// We handle errors just like any other message
+	case errMsg:
+		m.err = msg
+		return m, nil
+	}
+
+	return m, tea.Batch(tiCmd, vpCmd)
+}
+
+func (m model) View() string {
+	return fmt.Sprintf(
+		"%s\n\n%s",
+		m.viewport.View(),
+		m.textarea.View(),
+	) + "\n\n"
+}