4.3 KiB
COMS3011A Lab 1: Todo App
A local-first, single-user task management application built with Next.js App Router and SQLite (better-sqlite3).
Project Description
This project provides a task management interface designed for desktop usage. It features task creation, real-time sorting by topic, status, and due date, dynamic overdue detection, task editing, and soft-deletion (archiving) with unarchiving capabilities.
Architectural Choices & Key Decisions
-
Next.js App Router (Server Components & Server Actions):
- Server Components execute on Node.js, allowing direct SQLite queries without separate REST API setup.
- Server Actions handle form submissions securely on the server, eliminating client-side API boilerplate.
- Server cache revalidation (
revalidatePath('/')) keeps UI data in sync instantly after mutations.
-
SQLite via
better-sqlite3(Local-First):- Synchronous, file-based database stored directly in
todo.db. - Offers low latency and zero network dependencies.
- Synchronous, file-based database stored directly in
-
Dynamic Overdue State Derivation:
- Overdue status is computed dynamically at read-time by comparing
due_dateagainst the current date for non-completed tasks. - Overdue state is intentionally excluded as a database column to prevent stale data.
- Overdue status is computed dynamically at read-time by comparing
-
Soft-Deletion (Archiving):
- Tasks are never hard-deleted from SQLite. Archiving sets
is_archived = 1, preserving historical records while enabling restoration.
- Tasks are never hard-deleted from SQLite. Archiving sets
System Architecture UML Diagram
sequenceDiagram
autonumber
actor User
participant ClientComp as React Client Component
participant ServerAct as Server Action (actions.ts)
participant DataLayer as Data Access Layer (tasks.ts)
participant SQLite as SQLite DB (todo.db)
participant Page as Server Page (page.tsx)
User->>ClientComp: Submit Task / Action Trigger
ClientComp->>ServerAct: Invoke Server Action (formData)
ServerAct->>ServerAct: Validate Inputs & Guard Fields
ServerAct->>DataLayer: Call CRUD Function
DataLayer->>SQLite: Prepared Statement Execution (db.prepare)
SQLite-->>DataLayer: Operation Result
ServerAct->>ServerAct: revalidatePath('/')
ServerAct-->>ClientComp: Action Complete
ServerAct->>Page: Re-render Server Component
Page->>DataLayer: getTasks()
DataLayer->>SQLite: SELECT * FROM tasks WHERE is_archived = 0
SQLite-->>Page: Active Task Records
Page-->>User: Stream Updated UI HTML
Third-Party Packages & Justifications
| Package Name | Type | Justification |
|---|---|---|
better-sqlite3 |
Production | High-performance synchronous C-based SQLite driver for Node.js. |
@types/better-sqlite3 |
Development | TypeScript type definitions for SQLite query compilation. |
next |
Production | Full-stack React framework providing App Router and Server Actions. |
react / react-dom |
Production | UI rendering engine for component tree management. |
tailwindcss |
Development | Utility styling engine for global baseline styles. |
typescript |
Development | Static type checking across server and client boundaries. |
Environment Requirements & Running Instructions
Requirements
- Node.js version 18.x or higher
- npm package manager
Installation
npm install
Running the Application
npm run dev
Note: Next.js defaults to port 3000. If port 3000 is occupied, Next.js automatically selects the next available port (e.g. 3001), or you can specify a custom port using npm run dev -- -p <PORT_NUMBER>.
AI Usage Declaration
AI assistance was utilized during this project for architectural explanations, troubleshooting SQLite schema initialization, and reviewing TSX component patterns. All code additions were executed under guided pair-programming workflows.
Full session records and transcripts are declared in docs/AI_TRANSPARENCY.md.
Documentation Directory Index
All technical documentation modules are located inside the docs/ folder:
- Database Design Documentation - SQLite schema, column specifications, and design rationale.
- Entity Relationships Documentation - Class diagram, state transitions, and dynamic overdue rules.
- AI Transparency Declaration - AI usage breakdown, session transcripts, and prompt logs.