Learn Aria, Cloudflare and Css

Bootstrap is an incredibly popular CSS framework designed to make your website look great on mobile and desktop.

By the end of this course, you'll be familiar with many of the popular classes and components that Bootstrap uses to apply in your own projects.

For each feature you build in the course, you'll get a sense for what the relevant classes do for those components and links to documentation for further exploration.

For the course demo application, we will analyze the landing pages of Microsoft and Apple to identify common components that are implemented. When these are identified, you'll implement these components yourself with Bootstrap.

You'll build several common UI elements such as a nav bar, a carousel of images, Cards, and Forms.

Through building these components, you'll understand what is behind the different classes Bootstrap gives you and get familiar with how it exposes flex and grid layout for you.

Cascading Style Sheets bring order and beauty to our applications.

Create Professional Responsive Websites using Bootstrap

WAI-ARIA, the Accessible Rich Internet Applications Suite, defines a way to make Web content and Web applications more accessible to people with disabilities. It especially helps with dynamic content and advanced user interface controls developed with Ajax, HTML, JavaScript, and related technologies. 

aria

We'll go over the work it takes to use ARIA to show why Semantic HTML is almost always the safer bet. 

Create a Semantic Checkbox vs an ARIA Checkbox

Now that we have a project, we need a Pin input to work with. We'll create 4 inputs and style them so they look like a security code pin input that you would expect to see.

Style a Pin Input through Data Attributes in React

Debug Computed Accessibility Properties with Chrome Dev Tools

In this lesson, we use the element inspector in Chrome to test and improve our contrast to meet WCAG AA Contrast Ratio Standards.

Resources:
- [WebAIM - Contrast and Color Accessibility](https://webaim.org/articles/contrast/)

Debugging Accessible Contrast with Chrome Dev Tools

In this lesson, we are creating the audio player interface more visually appealing using icons from the React Icons library and Font Awesome, in this process, we are also ensuring that the interface remains accessible to screen readers by providing text descriptions for the icons, first by using the `title` prop on each icon, and then by implementing a `visually hidden` technique that hides the text descriptions from sighted users but makes them available to screen readers. This involves copying and pasting some CSS code to create a visually-hidden class, adding an `aria-hidden` attribute to each icon, wrapping each icon in a React fragment, and then adding a `span` element above each icon with the corresponding text description and the `visually-hidden` class.

**Think about:**  
- Why use `aria-hidden` or visually hide spans? 
- What value does this add to screen reader users?

Design Accessible Buttons Using Icons

In this lesson, we will create event listeners for the play and pause events on an audio player element and use these listeners to update the value of a variable called `isPlaying` that tracks the current state of the player (e.g., whether it is currently playing or paused). The event listeners, named `onPlay` and `onPause`, will be triggered when the user presses the play or pause button on the audio player element itself, not on a custom play button that may have been created.

Add Play and Pause Events to the Audio Player

We are creating an input of type range with an associated label, this input is to represent the current playback position in the audio, and the user will be able to change the playback position using the input.

The input value is set to be the media time state, it is added a minimum value of 0 and a maximum value as the duration. The demonstration shows how the media time state updates accordingly when the user changes the time using the input range.

A function called `onScrubberChange` is added, which takes in an event as an argument and `console.logs` the value of that event. The `onChange` event is added to the input, ensuring it works as expected. A variable sets the media time state and the current time on the audio ref.

**Think about:** Why do we use the `event.target.value` to set the new `mediaTime` (reminder that the value of the range is bound to `mediaTime`....maybe take a look at that with the formatter)

Create the Audio Scrubber to Control Playback Position

In this lesson, we are creating a new state called `mediaTime` with an initial value of 0, updating sample text in the markup to display the value of `mediaTime`, and adding an event listener to the audio element for the `timeUpdate` event.

In the `timeUpdate` event listener callback function, the `mediaTime` state is set to the audio element's current time, which can be accessed using the `audioRef.current.currentTime`. A function is added to the `onTimeUpdate` event of the audio element, to be able to track the current time. And a time formatter is added to format the time for displaying elapsed time and total time.

**Think about:** How often does onTimeUpdate update? (every second, not every millisecond) 

Tracking Audio Playback Progress by Adding Elapsed Time 

We created a duration state with an initial value of zero, then added an event listener to the audio element for the `loadedMetaData` event. In the event listener callback function, you set the duration state's value to be the audio element's current duration. This ensures that the value of the duration state is only set once the audio element metadata is loaded, allowing you to display the accurate total time of the audio file.

**Think about:** Why do we need to set the duration on the `onLoadedMetadata` event?

"The `onLoadedMetadata` event occurs when metadata for the specified audio/video has been loaded." You can read the docs [here](https://www.w3schools.com/tags/av_event_loadedmetadata.asp) 


 Implementing a Duration State 

Cloudflare secures and ensures the reliability of your external-facing resources such as websites, APIs, and applications. It protects your internal resources such as behind-the-firewall applications, teams, and devices. And it is your platform for developing globally-scalable applications.

cloudflare

Supabase Function Hooks allow us to subscribe to change events in the database - such as `insert`, `update` and `delete` - and make a HTTP request with the changed data.

In this lesson, we refactor our `revalidate` route to handle inserts, updates and deletes.

Additionally, we create a Function Hook to subscribe to all change events on the `articles` table, and automatically send a POST request to the `revalidate` route of our Cloudflare Worker.

This automatically refreshes the KV store anytime a value is changed in the database, and decouples the revalidation of our cache, from our user requesting data. This means, theoretically, users should never have to wait for a request to the Supabase origin server, as the cache is automatically populated, updated and cleared to remain in sync with the database.

## Code Snippets

**Update Revalidate route to handle insert, update and delete**

```javascript
router.post(
  "/revalidate",
  withContent,
  async (request, { SUPABASE_URL, SUPABASE_ANON_KEY, ARTICLES }) => {
    const { type, record, old_record } = request.content;
    const supabase = createClient(SUPABASE_URL, SUPABASE_ANON_KEY);

    if (type === "INSERT" || type === "UPDATE") {
      await writeTo(ARTICLES, `/articles/${record.id}`, record);
    }

    if (type === "DELETE") {
      await ARTICLES.delete(`/articles/${old_record.id}`);
    }

    const { data: articles } = await supabase.from("articles").select("*");
    await writeTo(ARTICLES, "/articles", articles);

    return json({ received: true });
  }
);
```

**Run wrangler development server**

```bash
npx wrangler dev
```

**Publish Cloudflare Worker with Wrangler CLI**

```bash
npx wrangler publish
```

## Resources

- [Supabase Functions blog](https://supabase.com/blog/2021/07/30/supabase-functions-updates#function-hooks-alpha)
- [Supabase.js docs](https://github.com/supabase/supabase-js)
- [Wrangler CLI docs](https://developers.cloudflare.com/workers/wrangler/commands/)
- [KV Storage docs](https://developers.cloudflare.com/workers/runtime-apis/kv/)

Automatically revalidate KV Store cache on change with Database Webhooks in Supabase

Cache Busting or Invalidation, is the process of clearing stale data from a cache. After the first request, the response data from Supabase is cached in our KV store, and never fetched again. This means if data in the database changes, our KV store will never be updated.

In this lesson, we create a `revalidate` route, which fetches fresh data from Supabase and updates the cache.

## Code Snippets

**Revalidate cache for articles route**

```javascript
router.get(
  "/revalidate",
  async (request, { SUPABASE_URL, SUPABASE_ANON_KEY, ARTICLES }) => {
    const supabase = createClient(SUPABASE_URL, SUPABASE_ANON_KEY);
    const { data: articles } = await supabase.from("articles").select("*");
    await writeTo(ARTICLES, "/articles", articles);
    return json({ received: true });
  }
);
```

**Run wrangler development server**

```bash
npx wrangler dev
```

## Resources

- [Supabase.js docs](https://github.com/supabase/supabase-js)
- [Wrangler CLI docs](https://developers.cloudflare.com/workers/wrangler/commands/)
- [KV Storage docs](https://developers.cloudflare.com/workers/runtime-apis/kv/)

Cache-busting with Cloudflare KV stores and Supabase

KV Storage is a read-optimized, eventually consistent cache that can be accessed from Cloudflare Workers. The interface for reading and writing is similar to `localStorage` in the browser.

In this lesson, we create a `read-kv` route for reading from the KV store. This automatically gets passed any KV stores that have been bound to the Cloudflare Worker. Initially, the store is empty, so returns the value `null`.

Additionally, we create a `write-kv` route to populate the store with test data.

To reduce the overhead of stringifying and parsing JSON objects, we create two helper functions to easily read and write values to any KV store.

Lastly, we publish a production version of our Cloudflare Worker, to confirm that writing these value locally - to our preview store - does not affect our production store.

## Code Snippets

**readFrom helper function**

```javascript
export const readFrom = async (cache, path) => {
  const data = await cache.get(path);
  return JSON.parse(data);
};
```

**writeTo helper function**

```javascript
export const writeTo = async (cache, path, data) => {
  await cache.put(path, JSON.stringify(data));
};
```

**Read KV route**

```javascript
router.get("/read-kv", async (request, { ARTICLES }) => {
  const articles = await readFrom(ARTICLES, "/articles");
  return json(articles);
});
```

**Write KV route**

```javascript
router.get("/write-kv", async (request, { ARTICLES }) => {
  const articles = [{ title: "test3" }, { title: "test4" }];
  await writeTo(ARTICLES, "/articles", articles);

  return json(articles);
});
```

**Publish Cloudflare Worker**

```bash
npx wrangler publish
```

**Run wrangler development server**

```bash
npx wrangler dev
```

## Resources

- [Wrangler CLI docs](https://developers.cloudflare.com/workers/wrangler/commands/)
- [KV Storage docs](https://developers.cloudflare.com/workers/runtime-apis/kv/)

Read and write KV Storage cache from Cloudflare Worker

Supabase is an open source Firebase alternative. A service to:

- Listen to database changes.
- Query your tables, including filtering, pagination, and deeply nested relationships (like GraphQL).
- Create, update, and delete rows.
- Manage your users and their permissions.
- Interact with your database using a simple UI.

Supabase is not a 1-to-1 mapping of Firebase. Most notably, Supabase uses Postgres rather than a NoSQL store. 

supabase

Itty Router is a tiny router package that has a similar API to Express. In this video, we install Itty Router and the Extras packages.

Additionally, we refactor our existing worker to use the router, and declare a dynamic route to fetch a single article.

To handle paths and articles that don't exist, we add a catch all route that returns a 404 status.

Lastly, we use the `json` helper to automatically stringify JSON objects and set the `Content-Type` header for `application/json`.

## Code Snippets

**Install Itty Router and extras**

```bash
npm i itty-router itty-router-extras
```

**Run wrangler development server**

```bash
npx wrangler dev
```

**GET route for all articles**

```javascript
router.get(
  "/articles",
  async (request, { SUPABASE_URL, SUPABASE_ANON_KEY }) => {
    const supabase = createClient(SUPABASE_URL, SUPABASE_ANON_KEY);

    const { data } = await supabase.from("articles").select("*");
    return json(data);
  }
);
```

**GET route for one article**

```javascript
router.get(
  "/articles/:id",
  async (request, { SUPABASE_URL, SUPABASE_ANON_KEY }) => {
    const supabase = createClient(SUPABASE_URL, SUPABASE_ANON_KEY);
    const { id } = request.params;

    const { data } = await supabase
      .from("articles")
      .select("*")
      .match({ id })
      .single();

    if (!data) {
      return status(404, "Not found");
    }

    return json(data);
  }
);
```

**Catch all route for 404**

```javascript
router.all("*", () => status(404, "Not found"));
```

## Resources

- [Itty Router repo](https://github.com/kwhitley/itty-router)
- [Itty Router Extras repo](https://github.com/kwhitley/itty-router-extras)

Proxy Supabase requests with Cloudflare Workers and Itty Router

Supabase JS is an NPM package which provides a simple interface from JavaScript to our Supabase project. It allows us to query and mutate data using its Object Relational Mapping (ORM) syntax, and subscribe to realtime events.

In this video, we install the Supabase JS package and create a new client using our project's URL and Anon Key. These can be found in the Supabase dashboard for our project, under `Settings > API`.

We store these values as secrets in our Cloudflare account, and use them to instantiate a new Supabase client.

Additionally, we write a query to select all of our articles from our Supabase instance, and send them back as the response from our Cloudflare Worker.

In order to send a JSON response, we first stringify the object we get back from Supabase, and then set a `Content-Type` header to notify the browser that this will be a type of `application/json`.

## Code Snippets

**Install Supabase JS**

```bash
npm i @supabase/supabase-js
```

**Create a Cloudflare secret**

```bash
npx wrangler secret put NAME
```

**Add a secret for SUPABASE_URL**

```bash
npx wrangler secret put SUPABASE_URL
```

**Run wrangler development server**

```bash
npx wrangler dev
```

**Add a secret for SUPABASE_ANON_KEY**

```bash
npx wrangler secret put SUPABASE_ANON_KEY
```

**Query data from Supabase**

```javascript
const { data } = await supabase.from("articles").select("*");
```

**Send JSON response**

```javascript
return new Response(JSON.stringify(data), {
  headers: {
    "Content-Type": "application/json",
  },
});
```

## Resources

- [Selecting data with Supabase JS](https://supabase.com/docs/reference/javascript/select)
- [Introducing Secrets and Environment Variables to Cloudflare Workers](https://blog.cloudflare.com/workers-secrets-environment/)
- [Cloudflare docs for sending JSON responses](https://developers.cloudflare.com/workers/examples/return-json/)

Query Supabase from Cloudflare Worker

Cloudflare Workers are serverless functions that run at the Edge! 🔪

The Wrangler CLI is a tool for interfacing with your Cloudflare account, and creating or publishing your Workers.

In this video, we use the Wrangler CLI to log in to our Cloudflare account and authorize the `wrangler` command to make changes on our behalf.

Additionally, we create a worker and host it locally with the `npx wrangler dev` command. We then demonstrate making a GET request to our Cloudflare Worker from the browser, and confirm it is sending the correct response.

By modifying the response locally, we can see that changes are reflected any time we refresh the browser.

## Code Snippets

**Login to Cloudflare with Wrangler CLI**

```bash
npx wrangler login
```

**Create Cloudflare Worker**

```bash
npx wrangler init supabase-at-the-edge
```

**Run wrangler development server**

```bash
npx wrangler dev
```

## Resources

- [Cloudflare Wrangler docs](https://developers.cloudflare.com/workers/wrangler/get-started/)

Create a Cloudflare Worker with the Wrangler CLI

We've seen how to return easy and a little complex data from our KV, but how about in a real-world application? We are going to remove the code we have created and set up a simple HTML application that will return our data based on an API which we will create. 

Update Cloudflare Workers KVs Data from an API Route

Behind the scenes, I've updated the HTML UI and added in some helper JS functions to allow us to render new to-do's. We are going to start off by adding in the UI for a user to be able to input their own to-dos. Then we are going to work on creating a backend to store that data and retrieve it using our KV key of `"data"`. 

Filter Data with Cloudflare Workers KV Keys

Our application works but there is one major flaw. Everyone sees the same to-do's. To make to-do's user-specific, we are going to link users' data to their IP addresses so people only see to-dos based on their IP address. 

Identify Users in a Cloudflare Worker by IP to Serve User-specific Data

Now that we have our Workers project up and running, we need to create a KV namespace. A KV namespace is a key-value database that is replicated to Cloudflare's edge. Using the terminal, we will create our namespace and add it to our wrangler.toml file. 

Create a Cloudflare Workers KV Namespace

Creating a new workers project using Wrangler is pretty easy. We first will install and double-check that we have Wrangler installed. Then we will connect Wrangler to our cloudflare project. Lastly, using the terminal, we can easily create our new Wrangler project. 

Create a New Cloudflare Workers Project with Wrangler

Speed up your bug-fixing process dramatically with Cursors Composer. Take a warning from your logs, search for relevant terms, then seamlessly import both the warning and search results into Composer. Add documentation and apply fixes to all search results in one go. This streamlined workflow resolves multiple issues rapidly, saving valuable development time.

Batch Fix Every File in Search Results with Cursor's Composer

 We map over the initial set of results then use `Promise.all` to efficiently fetch the details of each pokemon rendered in the table. This allows us to add more columns to our pokemon table.

Fetch and display row details with Promise.all in Tanstack Table

map over the initial set of results then use `Promise.all` to efficiently fetch the details of each pokemon rendered in the tanstack table

Create a custom hook to fetch remote data by passing a promise to the React 19 `use` hook. Then render this data in Tanstack Table by memoizing the results and passing them to `useReactTable`.

Render remote data in a Tanstack Table with React 19's use hook and a promise

Create a custom hook using React 19’s use to fetch data with a promise. Render it in a Tanstack Table by memoizing and using useReactTable.

You know when you're deep in the code trenches and need someone to challenge your assumptions? That's exactly what this is about.

Instead of waiting for someone to poke holes in your master plan, you can paste that strategy straight into AI Studio and let it pressure test your ideas. We're talking about using this tool to validate everything from your feature proposals to your ambitious refactoring strategies.

The real magic happens when you hit that microphone button. Now you're in a real-time verbal sparring match. It's like rubber duck debugging but the duck actually pushes back and makes you defend every architectural decision you've made.

Here's the workflow:
1. Drop your master plan into the system instructions
2. Tell the AI to challenge every assumption
3. Hit that mic and defend your choices like you mean it
4. Watch your plan either emerge stronger or get rightfully dismantled

This approach is perfect when you're:
- Stuck in your own head with a complex problem
- Need to validate if your approach holds water
- Want to catch edge cases before they catch you
- Looking for opportunities you might have missed because you're too close to the code

It's like having a senior dev on call 24/7, ready to challenge your ideas and push you to think deeper about your solutions.

Now go forth and get your ideas challenged. Your projects will thank you for it.


An Uncomfortable and Challenging Conversation with AI Studio

In this lesson, you'll learn how to effectively brainstorm your project ideas before working with AI agents. We'll cover:

1. The importance of having a clear plan before starting work with AI agents
2. Using traditional brainstorming techniques to gather your thoughts
3. Leveraging video recording to capture your brainstorming session
4. How to review and analyze websites for inspiration
5. Documenting likes, dislikes, and potential features for your project
6. Using AI tools (like AI Studio) to organize and process your recorded brainstorming session

The lesson emphasizes a modern approach to brainstorming that combines traditional techniques with video recording, making it easier to later process your ideas through AI tools. This method helps ensure that no ideas are lost and that your thoughts can be effectively organized by AI for future reference.

How to Brainstorm Your Project Features to Prepare for AI Agents

Many people share .cursorrules files, but trying to craft your own from scratch is a huge pain. Instead, this lesson shows you how to grab ALL community-created .cursorrules files to build a custom rule set for your projects. We'll use Gitingest and Google AI Studio to gather these examples and generate an awesome starting point customized to your specific project.

Generate Custom .cursorrules for Your Project Based on Community Examples

The GitHub CLI allows you to search issues and filter on different criteria like amount of comments. This allows you to search for real-world situations and pains/solutions people have using different technology. 

With the GitHub CLI in hand we'll drop 100s of issues as context in Googles AI Studio and have Gemini determine the 10 most frequently asked questions. This will give us a sense of how people use a library and where people get hung up.

Search 100s of Issues with GitHub CLI as Context for AI Studio

I often find myself wondering how to use certain APIs in certain situations, and I have a couple of keywords that I try and search up on Google. 

What you can do in this situation is turn to GitHub and see how other people have actually used this code on public projects. The GitHub CLI enables us to run searches like this, and we can take the results and work on them programmatically.

Inside of Cursor with their Composer AI agent, we can search for the files we want, tell the agent to download them, and inspect them for better understanding of how those things work together.

Search All of GitHub's Code and Pass the Results to AI Agents in Cursor

Implement virtual scrolling to handle large datasets in an HTML table. Start with a basic table that renders 10,000 rows of data. The browser can struggle with this amount of DOM nodes to render at one time, especially on low end devices. 

We implement tanstack react virtual to render only the necessary amount of rows the user is viewing. The implementation includes proper column sizing, accessibility considerations, and convenient scroll controls, resulting in a smooth and performant table experience regardless of the dataset size.

Create a row virtualized HTML table with Tanstack Virtual

Learn how to implement virtual scrolling in React tables using TanStack Table and Tanstack Virtual with the useWindowVirtualizer React hook.

The most difficult tasks will require the strongest AI models. And those models simply aren't available as AI agents inside of your tooling. So the best workflows are to drag and drop the files you need to be changed and analyzed inside of a reasoning model such as OpenAI's O1 Pro, then letting it create a giant plan for your dumber AI agents to work on. The key here is that instead of just copying and pasting the entire plan into Cursors Composer or your AI agent, it's to create a file inside of your project and ask your agent to tackle the plan one step at a time. This allows you ample opportunity between each step to test and verify the micro steps along the way. Otherwise, as I've experienced many times, a session can go way off track and you burn a lot of time and burn a lot of AI requests Cursors Composer and it starts churning through a plan Cursors Composer and making lots of unwanted changes. Cursors Composer and it's to guide an AI agent to hold its hand along the way, especially through the most complex tasks. Cursors Composer and the most complex tasks Cursors Composer and the most complex tasks require a step-by-step plan.