create-modal
create-modal is a Claude Code skill from the marcus/sidecar repository that provides patterns and utilities for building declarative modal dialogs in Go applications. It covers modal types (confirm, input, select, form), section components (text, buttons, input fields, textarea, checkboxes, lists, conditional rendering), rendering with OverlayModal, and keyboard and mouse handling. Use this skill when implementing modal dialogs or confirmation windows in sidecar-based applications.
git clone --depth 1 https://github.com/marcus/sidecar /tmp/create-modal && cp -r /tmp/create-modal/.claude/skills/create-modal ~/.claude/skills/create-modalSKILL.md
# Creating Declarative Modals
Use the `internal/modal` package. The library handles keyboard navigation, mouse hit regions, hover states, and scrolling automatically.
## Quick Start
```go
import "github.com/marcus/sidecar/internal/modal"
// 1. Create the modal
m := modal.New("Delete Worktree?",
modal.WithWidth(58),
modal.WithVariant(modal.VariantDanger),
modal.WithPrimaryAction("delete"),
).
AddSection(modal.Text("Name: " + wt.Name)).
AddSection(modal.Spacer()).
AddSection(modal.Buttons(
modal.Btn(" Delete ", "delete", modal.BtnDanger()),
modal.Btn(" Cancel ", "cancel"),
))
// 2. Render in View
func (p *Plugin) View(width, height int) string {
background := p.renderListView(width, height)
rendered := p.myModal.Render(width, height, p.mouseHandler)
return ui.OverlayModal(background, rendered, width, height)
}
// 3. Handle input in Update
case tea.KeyMsg:
action, cmd := p.myModal.HandleKey(msg)
if action != "" {
return p.handleAction(action) // "delete", "cancel", etc.
}
return p, cmd
case tea.MouseMsg:
action := p.myModal.HandleMouse(msg, p.mouseHandler)
if action != "" {
return p.handleAction(action)
}
return p, nil
```
## Critical: Modal Initialization Pattern
The modal must exist before input handling. Create an `ensure` function called in **both** View and Update:
```go
func (p *Plugin) ensureMyModal() {
if p.targetItem == nil {
return // Required state missing
}
modalW := 50
if modalW > p.width-4 {
modalW = p.width - 4
}
if modalW < 20 {
modalW = 20
}
// Only rebuild if needed
if p.myModal != nil && p.myModalWidthCache == modalW {
return
}
p.myModalWidthCache = modalW
p.myModal = modal.New("Title", modal.WithWidth(modalW), ...).
AddSection(...)
}
```
**Call `ensureModal()` before the nil check in key handlers:**
```go
func (p *Plugin) handleMyModalKeys(msg tea.KeyMsg) tea.Cmd {
p.ensureMyModal() // CRITICAL: Before nil check
if p.myModal == nil {
return nil
}
action, cmd := p.myModal.HandleKey(msg)
// ...
}
```
Without this, the first keypress after opening drops because View runs after Update in bubbletea.
## Constructor and Options
```go
m := modal.New(title string, opts ...Option)
```
| Option | Description | Default |
|--------|-------------|---------|
| `WithWidth(int)` | Modal width in characters | 50 |
| `WithVariant(Variant)` | Visual style | `VariantDefault` |
| `WithPrimaryAction(string)` | Action ID for Enter on inputs | "" |
| `WithHints(bool)` | Show "Tab to switch..." hint | true |
| `WithCloseOnBackdropClick(bool)` | Backdrop click returns "cancel" | true |
**Variants:** `VariantDefault`, `VariantDanger` (red), `VariantWarning` (yellow), `VariantInfo` (blue)
## Built-in Sections
### Text and Spacer
```go
modal.Text("Static text with auto line wrapping")
modal.Spacer() // Single blank line
```
### Buttons
```go
modal.Buttons(
modal.Btn(" Save ", "save"), // Standard button
modal.Btn(" Delete ", "delete", modal.BtnDanger()), // Red
modal.Btn(" Submit ", "submit", modal.BtnPrimary()), // Primary
modal.Btn(" Cancel ", "cancel"),
)
```
- Include padding in labels: `" Save "` not `"Save"`
- Button IDs are returned as actions
- Tab/Shift+Tab cycles focus
### Input
```go
var nameInput textinput.Model
modal.Input("name-input", &nameInput)
modal.InputWithLabel("name-input", "Name:", &nameInput)
modal.Input("name-input", &nameInput,
modal.WithSubmitOnEnter(true), // Default: true
modal.WithSubmitAction("submit"), // Override primary action
)
```
### Textarea
```go
var msgArea textarea.Model
modal.Textarea("message", &msgArea, 5) // height in lines
modal.TextareaWithLabel("message", "Label:", &msgArea, 5)
```
- Enter inserts newlines (never submits)
### Checkbox
```go
var includeFiles bool
modal.Checkbox("include-files", "Include untracked files", &includeFiles)
```
- Enter or Space toggles
### List
```go
items := []modal.ListItem{
{ID: "item-1", Label: "First item", Data: someValue},
{ID: "item-2", Label: "Second item"},
}
var selectedIdx int
modal.List("my-list", items, &selectedIdx, modal.WithMaxVisible(5))
```
- j/k or up/down moves selection; Enter returns selected item's ID
### When (Conditional)
```go
modal.When(func() bool { return showWarning },
modal.Text("Warning: This action is irreversible!"),
)
```
### Custom
```go
modal.Custom(
func(contentWidth int, focusID, hoverID string) modal.RenderedSection {
return modal.RenderedSection{
Content: content,
Focusables: []modal.FocusableInfo{
{ID: "custom-btn", OffsetX: 0, OffsetY: 2, Width: 10, Height: 1},
},
}
},
func(msg tea.Msg, focusID string) (string, tea.Cmd) {
return "", nil // can be nil if no custom input handling
},
)
```
## Handling Input
### Keyboard
```go
action, cmd := m.HandleKey(msg)
```
| Key | Behavior |
|-----|----------|
| Tab | Focus next element |
| Shift+Tab | Focus previous element |
| Enter | Return focused element's ID (or primaryAction for inputs) |
| Esc | Return "cancel" |
| Other | Forwarded to focused section |
### Mouse
```go
action := m.HandleMouse(msg, p.mouseHandler)
```
| Event | Behavior |
|-------|----------|
| Click backdrop | Return "cancel" (if enabled) |
| Click button/checkbox | Return element ID |
| Hover element | Update hover state |
| Scroll on modal | Scroll content |
## Modal Methods
```go
m.FocusedID() string // Currently focused element ID
m.HoveredID() string // Currently hovered element ID
m.SetFocus(id string) // Focus specific element
m.Reset() // Reset focus, hover, scroll to initial state
```
## Rendering Rules
Always use `ui.OverlayModal` for dimmed background:
```go
func (p *Plugin) View(width, height int) string {
background := p.r>
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