BubbleTea Code Review

Quick Reference

Review Checklist

• Model is immutable (Update returns new model, not mutates)
• Init returns proper initial command (or nil)
• Update handles all expected message types
• View is a pure function (no side effects)
• tea.Quit used correctly for exit
• Key bindings use key.Matches with help.KeyMap
• Lipgloss styles are defined once, not in View
• Commands are used for I/O, not direct calls
• WindowSizeMsg handled for responsive layout
• tea.Batch used for multiple commands

Critical Patterns

Model Must Be Immutable

// BAD - mutates model
func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
    m.items = append(m.items, newItem)  // mutation!
    return m, nil
}

// GOOD - returns new model
func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
    newItems := make([]Item, len(m.items)+1)
    copy(newItems, m.items)
    newItems[len(m.items)] = newItem
    m.items = newItems
    return m, nil
}

Commands for Async/IO

// BAD - blocking in Update
func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
    data, _ := os.ReadFile("config.json")  // blocks UI!
    m.config = parse(data)
    return m, nil
}

// GOOD - use commands
func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
    return m, loadConfigCmd()
}

func loadConfigCmd() tea.Cmd {
    return func() tea.Msg {
        data, err := os.ReadFile("config.json")
        if err != nil {
            return errMsg{err}
        }
        return configLoadedMsg{parse(data)}
    }
}

Styles Defined Once

// BAD - creates new style each render
func (m Model) View() string {
    style := lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("205"))
    return style.Render("Hello")
}

// GOOD - define styles at package level or in model
var titleStyle = lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("205"))

func (m Model) View() string {
    return titleStyle.Render("Hello")
}

When to Load References

• Reviewing Update function logic → model-update.md
• Reviewing View function, styling → view-styling.md
• Reviewing component hierarchy → composition.md

Review Questions

1. Is the model immutable in Update?
2. Are I/O operations done via commands?
3. Are Lipgloss styles defined once, not in View?
4. Is WindowSizeMsg handled for resizing?
5. Are key bindings documented with help.KeyMap?