superpowers/tests/subagent-driven-dev/svelte-todo/plan.md

Svelte Todo List - Implementation Plan

Execute this plan using the superpowers:subagent-driven-development skill.

Context

Building a todo list app with Svelte. See design.md for full specification.

Tasks

Task 1: Project Setup

Create the Svelte project with Vite.

Do:

• Run npm create vite@latest . -- --template svelte-ts
• Install dependencies with npm install
• Verify dev server works
• Clean up default Vite template content from App.svelte

Verify:

• npm run dev starts server
• App shows minimal "Svelte Todos" heading
• npm run build succeeds

---

Task 2: Todo Store

Create the Svelte store for todo state management.

Do:

• Create src/lib/store.ts
• Define Todo interface with id, text, completed
• Create writable store with initial empty array
• Export functions: addTodo(text), toggleTodo(id), deleteTodo(id), clearCompleted()
• Create src/lib/store.test.ts with tests for each function

Verify:

• Tests pass: npm run test (install vitest if needed)

---

Task 3: localStorage Persistence

Add persistence layer for todos.

Do:

• Create src/lib/storage.ts
• Implement loadTodos(): Todo[] and saveTodos(todos: Todo[])
• Handle JSON parse errors gracefully (return empty array)
• Integrate with store: load on init, save on change
• Add tests for load/save/error handling

Verify:

• Tests pass
• Manual test: add todo, refresh page, todo persists

---

Task 4: TodoInput Component

Create the input component for adding todos.

Do:

• Create src/lib/TodoInput.svelte
• Text input bound to local state
• Add button calls addTodo() and clears input
• Enter key also submits
• Disable Add button when input is empty
• Add component tests

Verify:

• Tests pass
• Component renders input and button

---

Task 5: TodoItem Component

Create the single todo item component.

Do:

• Create src/lib/TodoItem.svelte
• Props: todo: Todo
• Checkbox toggles completion (calls toggleTodo)
• Text with strikethrough when completed
• Delete button (X) calls deleteTodo
• Add component tests

Verify:

• Tests pass
• Component renders checkbox, text, delete button

---

Task 6: TodoList Component

Create the list container component.

Do:

• Create src/lib/TodoList.svelte
• Props: todos: Todo[]
• Renders TodoItem for each todo
• Shows "No todos yet" when empty
• Add component tests

Verify:

• Tests pass
• Component renders list of TodoItems

---

Task 7: FilterBar Component

Create the filter and status bar component.

Do:

• Create src/lib/FilterBar.svelte
• Props: todos: Todo[], filter: Filter, onFilterChange: (f: Filter) => void
• Show count: "X items left" (incomplete count)
• Three filter buttons: All, Active, Completed
• Active filter is visually highlighted
• "Clear completed" button (hidden when no completed todos)
• Add component tests

Verify:

• Tests pass
• Component renders count, filters, clear button

---

Task 8: App Integration

Wire all components together in App.svelte.

Do:

• Import all components and store
• Add filter state (default: 'all')
• Compute filtered todos based on filter state
• Render: heading, TodoInput, TodoList, FilterBar
• Pass appropriate props to each component

Verify:

• App renders all components
• Adding todos works
• Toggling works
• Deleting works

---

Task 9: Filter Functionality

Ensure filtering works end-to-end.

Do:

• Verify filter buttons change displayed todos
• 'all' shows all todos
• 'active' shows only incomplete todos
• 'completed' shows only completed todos
• Clear completed removes completed todos and resets filter if needed
• Add integration tests

Verify:

• Filter tests pass
• Manual verification of all filter states

---

Task 10: Styling and Polish

Add CSS styling for usability.

Do:

• Style the app to match the design mockup
• Completed todos have strikethrough and muted color
• Active filter button is highlighted
• Input has focus styles
• Delete button appears on hover (or always on mobile)
• Responsive layout

Verify:

• App is visually usable
• Styles don't break functionality

---

Task 11: End-to-End Tests

Add Playwright tests for full user flows.

Do:

• Install Playwright: npm init playwright@latest
• Create tests/todo.spec.ts
• Test flows:
  • Add a todo
  • Complete a todo
  • Delete a todo
  • Filter todos
  • Clear completed
  • Persistence (add, reload, verify)

Verify:

• npx playwright test passes

---

Task 12: README

Document the project.

Do:

• Create README.md with:
  • Project description
  • Setup: npm install
  • Development: npm run dev
  • Testing: npm test and npx playwright test
  • Build: npm run build

Verify:

• README accurately describes the project
• Instructions work