Project 02 Sprint 2 MVP Vertical Slice A Comprehensive Guide

Hey guys! Let's dive deep into Project 02 Sprint 2, focusing on the Minimum Viable Product (MVP) vertical slice. This sprint is all about building a functional skeleton of our Single Page Application (SPA). We'll cover everything from setting up the basic structure to implementing data persistence. So, buckle up and let's get started!

Understanding the Task: Building Our MVP

The main goal for this sprint is to ship a running SPA skeleton. Think of it as the foundational structure that will support our entire application. This includes implementing one complete vertical slice, which means handling the entire process from user input to rendering the output, managing application state, and persisting data. Specifically, we need to handle GET requests with Time-To-Live (TTL), manage states, and use JSONBin for PUT/POST operations for smaller artifacts. Plus, we’re aiming for a local-first boot and merge strategy. Sounds like a lot? Let’s break it down!

Key Components of the MVP

To achieve our goal, we need to focus on several key components:

1. Single-Page Shell with Router/View Manager + Central Store: This forms the backbone of our SPA. We need a router to handle navigation between different views and a view manager to render the appropriate components. A central store, like Redux or Vuex, will help us manage the application state efficiently.

   • Why a Single-Page Application (SPA)? SPAs provide a fluid user experience by loading a single HTML page and dynamically updating the content as the user interacts with the app. This eliminates the need to reload the entire page for every interaction, making the application feel faster and more responsive. SPAs are great for complex web applications that require rich user interfaces and seamless navigation. Libraries and frameworks like React, Angular, and Vue.js make it easier to build and manage SPAs.

   • Router and View Manager: The router is responsible for handling navigation within the SPA. It maps different URLs to specific views or components. When a user navigates to a new URL, the router updates the view accordingly. The view manager is then responsible for rendering the correct component based on the current route. Popular routing libraries include React Router for React applications, Angular Router for Angular applications, and Vue Router for Vue.js applications.

   • Central Store: A central store is a container that holds the entire application state. This makes it easier to manage and share state across different components. Centralized state management also simplifies debugging and testing. Redux is a popular choice for managing state in React applications, while Vuex is the official state management library for Vue.js applications. Context API is another option for smaller applications or when you don't need the full power of Redux or Vuex.

2. ≥3 Domain Classes: We need to define at least three domain classes. These are the core entities in our application’s domain. Think of them as the main data models we’ll be working with. For example, if we were building a to-do app, our domain classes might be Task, User, and Category.

   • What are Domain Classes? Domain classes represent the core concepts and entities in your application's domain. They encapsulate the data and behavior related to these entities. By defining domain classes, you create a structured representation of your application's data model. This makes it easier to reason about your application's logic and to maintain the codebase over time.

   • Examples of Domain Classes: In an e-commerce application, domain classes might include Product, Customer, Order, and ShoppingCart. In a social media application, they might include User, Post, Comment, and Like. The specific domain classes you need will depend on the nature of your application. It's important to carefully consider the core concepts in your domain and to design your classes to accurately reflect these concepts.

   • Designing Effective Domain Classes: When designing domain classes, focus on identifying the key attributes and behaviors of each entity. Attributes represent the data associated with the entity, while behaviors represent the actions that the entity can perform. Classes should be cohesive, meaning they should have a single, well-defined purpose. Aim for loose coupling between classes to make your application more flexible and maintainable. This means minimizing dependencies between classes so that changes in one class are less likely to affect other parts of the application.

3. ≥6 ES Modules: Our project should be structured using at least six ES modules. This promotes modularity and maintainability. ES modules allow us to break our code into smaller, reusable pieces, making it easier to manage and understand.

   • Why Use ES Modules? ES Modules (ECMAScript Modules) are a standardized way of organizing JavaScript code into reusable modules. They offer several advantages over traditional JavaScript modules, including improved code organization, better dependency management, and enhanced performance. By using ES modules, you can break your code into smaller, self-contained units, making it easier to maintain and reuse. ES modules also support features like tree shaking, which allows you to remove unused code from your final bundle, reducing the overall size of your application.

   • Benefits of Modularity: Modularity is a key principle of good software design. By breaking your code into modules, you can create a more maintainable and scalable application. Modules encapsulate specific functionality, making it easier to understand and test individual components. This also promotes code reuse, as you can import and use modules in different parts of your application. ES modules provide a native way to implement modularity in JavaScript, making it easier to build complex applications.

   • Best Practices for ES Modules: When working with ES modules, it's important to follow best practices for module design. Each module should have a clear purpose and should encapsulate a specific set of functionality. Avoid creating overly large modules, as this can make your code harder to understand and maintain. Use descriptive names for your modules and exports to make your code more readable. Consider organizing your modules into directories based on their functionality to create a clear and logical structure for your codebase.

4. Retry/Backoff + AbortController: We need to implement retry and backoff strategies for handling failed requests, along with AbortController for managing asynchronous operations. This ensures our application is resilient and can handle network issues gracefully.

   • Handling Asynchronous Operations: Asynchronous operations, such as making API requests, are a common part of web applications. However, these operations can sometimes fail due to network issues or server problems. It's important to implement strategies for handling these failures to ensure that your application remains responsive and reliable. Retry and backoff are two such strategies that can help you gracefully handle transient errors.

   • Retry and Backoff: The retry pattern involves automatically retrying a failed operation after a certain delay. This can be useful for handling temporary network issues or server downtime. However, it's important to implement a backoff strategy to avoid overloading the server with repeated requests. Backoff involves increasing the delay between retries over time. This gives the server a chance to recover and reduces the likelihood of exacerbating the problem.

   • AbortController: The AbortController API provides a way to cancel asynchronous operations, such as fetch requests. This can be useful for scenarios where a user navigates away from a page before a request completes or when you want to implement a timeout for a request. By using AbortController, you can prevent unnecessary network traffic and improve the performance of your application. It allows you to signal to the fetch operation that it should be aborted, preventing the application from wasting resources on requests that are no longer needed.

5. 30–60s GIF of Local Boot → GET → Render → PUT/POST: We need to create a short GIF demonstrating the core functionality of our MVP. This GIF should show the application booting locally, making a GET request, rendering the data, and performing PUT/POST operations.

   • Demonstrating Core Functionality: Creating a GIF to demonstrate the core functionality of your MVP is an effective way to showcase your work. It provides a visual overview of how the application works and highlights the key features you've implemented. The GIF should be concise and focus on the most important aspects of your application. This helps stakeholders quickly understand the value of your work and provides a clear picture of the application's functionality.

   • Steps for Creating an Effective GIF: To create an effective GIF, start by planning what you want to demonstrate. Focus on the core features and the key user flows. Record a video of your application in action, making sure to highlight the different steps clearly. Use screen recording software to capture the video, and then use a GIF creation tool to convert the video into a GIF. Keep the GIF short and to the point, ideally between 30 and 60 seconds. Add captions or annotations if necessary to explain what's happening in the GIF.

   • Tools for Creating GIFs: Several tools are available for creating GIFs from screen recordings. Some popular options include LiceCap, ScreenToGif, and Giphy Capture. These tools allow you to record your screen, trim the video, and convert it into a GIF format. Some tools also offer additional features, such as adding text annotations, adjusting the frame rate, and optimizing the GIF for web use. Choose a tool that meets your needs and is easy to use. Experiment with different settings to achieve the best balance between quality and file size.

6. README MVP Section Updated: Our README file should have an updated MVP section describing the functionality and how to run the application. This is crucial for anyone who wants to understand or contribute to our project.

   • Importance of a Well-Documented README: A well-documented README file is essential for any software project. It serves as the first point of contact for anyone who wants to understand, use, or contribute to your project. A comprehensive README provides an overview of the project, explains how to set it up, and outlines how to use it. It also includes information about the project's architecture, dependencies, and contribution guidelines. A clear and informative README can significantly improve the usability and maintainability of your project.

   • Key Sections of an MVP README: The MVP section of your README should focus on the core functionality of your application. Start by providing a brief overview of the MVP and its purpose. Explain what the MVP is intended to achieve and who the target users are. Then, describe the key features of the MVP and how they work. Include instructions on how to set up the application, run it locally, and use its core features. Add screenshots or GIFs to illustrate the functionality. Finally, provide information about any known limitations or issues with the MVP. This helps users understand the current state of the application and what to expect.

   • Best Practices for Writing a README: When writing a README, aim for clarity and conciseness. Use clear and simple language, and avoid jargon or technical terms that your audience may not understand. Organize your README into logical sections with clear headings and subheadings. Use bullet points, lists, and code snippets to break up large blocks of text. Keep your README up-to-date as your project evolves. Regularly review and update the README to reflect changes in the application's functionality or setup process. A well-maintained README is a valuable asset for your project.

Diving Deeper: Technical Requirements

Let's break down the technical requirements a bit more. We need to ensure our application meets the following criteria:

• ≥3 Domain Classes: We talked about this earlier. Make sure these classes are well-defined and encapsulate the core data of our application.
• ≥6 ES Modules: This means our codebase should be modular. Each module should have a specific purpose, making our code easier to maintain and test.
• Retry/Backoff + AbortController: These are crucial for handling network requests. Retry and backoff ensure our application can recover from temporary failures, while AbortController allows us to cancel requests if needed.

Code Examples and Best Practices

To help you guys visualize this, let’s look at some code examples and best practices.

ES Module Example

Let's say we have a module for handling user authentication:

// auth.js
export async function login(username, password) {
 try {
 const response = await fetch('/api/login', {
 method: 'POST',
 headers: {
 'Content-Type': 'application/json',
 },
 body: JSON.stringify({ username, password }),
 });

 if (!response.ok) {
 throw new Error('Login failed');
 }

 return await response.json();
 } catch (error) {
 console.error('Login error:', error);
 throw error;
 }
}

export function logout() {
 // Logout logic here
 console.log('User logged out');
}

Retry/Backoff Implementation

Here’s an example of how to implement retry and backoff:

async function fetchDataWithRetry(url, options, maxRetries = 3, backoffDelay = 1000) {
 for (let attempt = 0; attempt < maxRetries; attempt++) {
 try {
 const response = await fetch(url, options);
 if (response.ok) {
 return response;
 }
 console.log(`Attempt ${attempt + 1} failed with status: ${response.status}`);
 } catch (error) {
 console.error(`Attempt ${attempt + 1} failed with error:`, error);
 }

 await new Promise(resolve => setTimeout(resolve, backoffDelay * (attempt + 1)));
 }

 throw new Error('Max retries reached');
}

This function attempts to fetch data from a given URL. If it fails, it retries up to maxRetries times, increasing the delay between each attempt using a backoff strategy. This ensures that the application can handle temporary network issues gracefully.

AbortController Example

Here’s how to use AbortController to cancel a fetch request:

const controller = new AbortController();
const signal = controller.signal;

async function fetchData(url) {
 try {
 const response = await fetch(url, { signal });
 if (!response.ok) {
 throw new Error(`HTTP error! status: ${response.status}`);
 }
 return await response.json();
 } catch (error) {
 if (error.name === 'AbortError') {
 console.log('Fetch aborted');
 } else {
 console.error('Fetch error:', error);
 }
 }
}

// Abort the fetch request after 5 seconds
setTimeout(() => {
 controller.abort();
}, 5000);

In this example, we create an AbortController and pass its signal to the fetch options. If we call controller.abort(), the fetch request will be cancelled, and the promise will reject with an AbortError. This is particularly useful for scenarios where you need to cancel a request if the user navigates away from a page or if a timeout occurs.

JSONBin for PUT/POST Operations

For persisting smaller artifacts, we’re using JSONBin. This is a simple and convenient way to store JSON data. Here’s a quick example of how to use it:

POST Request

async function postData(data) {
 const response = await fetch('https://jsonbin.io/api/bins', {
 method: 'POST',
 headers: {
 'Content-Type': 'application/json',
 'Authorization': 'secret-key',
 },
 body: JSON.stringify(data),
 });

 return await response.json();
}

PUT Request

async function updateData(binId, data) {
 const response = await fetch(`https://jsonbin.io/api/bins/${binId}`, {
 method: 'PUT',
 headers: {
 'Content-Type': 'application/json',
 'Authorization': 'secret-key',
 },
 body: JSON.stringify(data),
 });

 return await response.json();
}

Remember to replace 'secret-key' with your actual JSONBin secret key. These functions allow you to easily post new data and update existing data in your JSONBin containers.

Meeting the Due Date and Acceptance Criteria

The due date for this sprint is October 8, 2025, at 23:59:00-05:00. Make sure you guys manage your time effectively to meet this deadline. To ensure our work is accepted, we need to meet the following criteria:

• Single-page shell with router/view manager + central store: This is the foundation of our SPA. Without it, the rest of the functionality won’t work.
• ≥3 domain classes; ≥6 ES modules; retry/backoff + AbortController where relevant: These ensure our code is well-structured, maintainable, and resilient.
• 30–60s GIF of local boot → GET → render → PUT/POST; README MVP section updated: This demonstrates our application’s core functionality and provides documentation for others to understand and use our work.

Tips for Success

• Start Early: Don’t wait until the last minute to start working on this. The earlier you start, the more time you’ll have to tackle any challenges that come up.
• Break Down the Task: This sprint has several components. Break it down into smaller, manageable tasks. This will make the overall project seem less daunting.
• Collaborate: If you’re working in a team, collaborate effectively. Share your progress, ask for help when you need it, and help others when you can.
• Test Your Code: Regularly test your code to ensure it’s working as expected. This will help you catch bugs early and prevent them from becoming bigger issues later on.
• Document Your Work: Keep your README updated as you progress. This will save you time later when you need to create the MVP section.

Final Thoughts

Project 02 Sprint 2 is a crucial step in building our application. By focusing on the MVP vertical slice, we’re laying a solid foundation for future development. Remember to focus on building a functional skeleton, managing state effectively, and persisting data using JSONBin. By meeting the acceptance criteria and managing our time effectively, we can ensure a successful sprint. Good luck, guys, and let’s build something amazing!