Learn Aria, Css and Solidity

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 

Ethereum is a decentralized, open-source blockchain with smart contract functionality. 

ethereum

Welcome to Noah's course on Introduction to Smart Contracts with Ethereum and Solidity. 

Introduction to Introduction to Smart Contracts with Ethereum and Solidity

Web3 is a paradigm shift in how applications are interacted with, ran, and built. 

It’s not just a Pump-and-Dump scheme on cryptocurrencies or Bored Ape NFT profile pictures you can put on Twitter.

A fundamental tenet of Web3 is bringing ownership back to the user. You no longer have to trust that your data is being properly handled on someone else’s server (although, currently Web3 ecosystem mainly depends on centralized infrastructure such as GitHub).  

This ownership is achieved through blockchain, cryptocurrencies, NFTs, and smart contracts.

A great example of this type of ownership is through how you exchange money in Web3. There is no intermediary like Stripe, or PayPal to process your transactions. You can even build your own smart contracts that receive crypto (e.g. Ethereum or ‘eth’ for short) and then process that eth how you’d like.

Building this type of smart contract is exactly what Matías is going to show you how to do right now.

Matías builds out a Web3 application that allows you to receive tips in the form of eth in a tip jar on your website. This means your application will be backed by a smart contract that’s accepts eth, stores data, and emits Solidity events.

The frontend application uses SvelteKit which you’ll see how easy it is to get up and be productive with in minutes. A huge benefit here is that the JavaScript you write is just that, JavaScript. You’ll be able to take what you learn and implement it into any framework of your choosing.

While you build this application you will learn how to:

- Write a smart contract using Solidity language
- Test the smart contract using just JavaScript through the waffle framework
- Communicate and interact with the smart contract using ethers.js in a SvelteKit application
- Deploy your smart contract to make it public and accessible to anyone

Solidity is an object-oriented, high-level language for implementing smart contracts.

solidity

Full Stack Web3 and Blockchain Development on Ethereum with SvelteKit

There are several Ethereum test networks like Ropsten, Rinkeby and Kovan that you can use to deploy your contract to have it publicly available without having to use the mainnet and real ETH.
In this course you'll deploy to Rinkeby netwok (but, the process is the same for the other networks).

The first step will be update your Metamask Wallet to connect to the Rinkeby network.

Next, you'll need some test/fake Ethere to use for testing the Dapp in the network, for that you'll need to use a [faucet like this one](https://www.rinkebyfaucet.com/). Just visit that faucet and add your wallet address.

You will also deploy your web application to vercel to see your project live on the internet!

Deploy your Smart Contract to Goerli Test Network and App to Vercel

The magical disappearing UI framework

 - The web's JavaScript bloat crisis, solved. Svelte turns your templates into tiny, framework-less vanilla JavaScript.
 - Simple and familiar. Build apps out of composable, easy-to-write blocks using languages you already know.
 - Super fast, rock solid. Compile-time static analysis ensures the browser does no more work than it needs to.

svelte

Now that we have an application that is accepting tips to the smart contract that was defined, we need to be able to withdraw the funds that are sent to the contract. The smart contract function for this is already defined so we will just need to call the function from the front end.

To do this we will create a new route to display the contract information. We will then check if the current user is the contract owner and if so allow that user to withdraw the contract funds by clicking a button that we wire up to call the withdraw function from the smart contract.

## Important

SvelteKit is still in beta. Expect bugs! Read more here, and track progress towards 1.0 here. 

This lesson was recorded before the latest breaking changes, the content is still valid but it sometimes references a file that does not exists anymore.

Now: 
`src/routes/index.svelte` is called `src/routes/+page.svelte`

`src/routes/__layout.svelte` is called `src/routes/+layout.svelte`


Everything else is 100% valid. This particular content will be updated when Sveltekit reaches 1.0.0 stable.

Withdraw eth from a Smart Contract in a Svelte Application

It is time to interact with the contract, let's send some eth!

For this you'll need a form that is rendered only when the wallet is connected.
This form use the `sendTip` function and gather some required information. On submit, it will read the `sendingTip` loading state variable and disable or enable the button.

## Important

SvelteKit is still in beta. Expect bugs! Read more here, and track progress towards 1.0 here. 

This lesson was recorded before the latest breaking changes, the content is still valid but it sometimes references a file that does not exists anymore.

Now: 
`src/routes/index.svelte` is called `src/routes/+page.svelte`

`src/routes/__layout.svelte` is called `src/routes/+layout.svelte`


Everything else is 100% valid. This particular content will be updated when Sveltekit reaches 1.0.0 stable.

Create a Form in Svelte and Send a Tip to an Solidity Smart Contract

Now is time to setup the client to talk with the contract, for that you will need to store and access the contract ABI (this is a file generated by the contract compilation) as well as use ethers to set up a connection to the contract. 

Once set up is complete, we will listen to any tip events that come in from the contract and display tip information in the application.

## Important

SvelteKit is still in beta. Expect bugs! Read more here, and track progress towards 1.0 here. 

This lesson was recorded before the latest breaking changes, the content is still valid but it sometimes references a file that does not exists anymore.

Now: 
`src/routes/index.svelte` is called `src/routes/+page.svelte`

`src/routes/__layout.svelte` is called `src/routes/+layout.svelte`


Everything else is 100% valid. This particular content will be updated when Sveltekit reaches 1.0.0 stable.

Interact with a Solidity Smart Contract Using Ethers and the Contract ABI in SvetleKit

Now the UI is capable to connect to the Ethereum network by using the wallet, but we need two more things to continue.

1. Avoid re-connecting every time the browser is refreshed
2. Get more information about the user and the network.

For the first, let's run a little function every time the component is mounted.

Then, let's read and display some more information:

- The user balance
- The network that the user is currently connected

## Important

SvelteKit is still in beta. Expect bugs! Read more here, and track progress towards 1.0 here. 

This lesson was recorded before the latest breaking changes, the content is still valid but it sometimes references a file that does not exists anymore.

Now: 
`src/routes/index.svelte` is called `src/routes/+page.svelte`

`src/routes/__layout.svelte` is called `src/routes/+layout.svelte`


Everything else is 100% valid. This particular content will be updated when Sveltekit reaches 1.0.0 stable.


Retrieve Ethereum Network and Account information on Mount and Display it in Svelte

The first step in this part of the journey, will be to setup a simple UI that allow you to connect the current user to the blockchain through it's wallet.

To do this, let's write some code.

Sveltekit applications works by using a file system routing method, meaning that you need to create files under the `src/routes/` folder and those will be then reflected as routes (urls) in your app. Let's keep ti simple and just use the default route here, open `src/routes/index.svelte` and delete the content of it.

You're first step will be create a button that allow the user to "sing-in" to your new dapp and allow the UI to react to that showing a different content if the authorization process was successful.


Connect a Metamask Account to a Svelte Application

Before jumping into the Dapp code you need to setup an Ethereum wallet.
There are bunch of wallet applications and types outher, but for this project we're going to use Metamask.

### What is an ethereum Wallet

A wallet is an application that let's you interact with your Ethereum account. You're wallet is the one that works as a gate between the Dapp and your data, through it the applications can read your balance, send transactions, etc.

You can swap wallet providers at any time or manage multiple accounts in one application. This is because the wallet are non-custodial, meaning that they don't hold your assets, you do.

Just to set some concepts down:

- An Ethereum account is an "entity" that can send transactions and store some assets, it "lives" inside the blockchain.
- The accout have an address (like your profile URL of some social app or your email address) that can be used to send or receive funds.
- A wallt is an application that allow you to interact with the Ethereum account.

There are different types of Wallets:

- Hardware wallets that hold your crypto assets offline - The most secure of all
- Mobile apps, like Argent.
- Web wallets, that let you interact through the browser: Like Metamask.
- Desktp apps

Set up a Metamask Wallet with your local Ethereum Network

Now you need a way to keep a local network alive, deploy the smart contract there and then interact with it. You can think on this like a local web server. When you develop an API you have a local server running it so the client application can talk to it so you can develop and test, this is the same idea.

Head over to your terminal and run tthe following command.

```bash
$ npm run hardhat node
```

This will ramp up a local ethreum network using hardhat and will show in the console a set of accounts and private keys that can be used for testing pruposes.

These are 20 test accounts and addresses created for your. Each account is also rich! are loaded with 10000 ETH. (fake eth btw).

Right now this is just an empty blockchain. There are no blocks nor smart contracts on it. But you want to create a new block and put the smart contract that you just created there, for that you need to create a little script that will use ethers.js power to compile and deploy.

Deploy a Solidity Smart Contract with Hardhat to a Local Ethereum Network

To reduce the amount of gas used, we will create a withdraw function that lets the owner of the contract withdraw funds that have been added when they want rather than withdraw with every transaction.

Your smart contract is ready to be used, since you have confidence in the code after testing it.

But there are a few things that you can add to improve the behavior and security of it.

Let's start by adding events.

Similar to any other programming language Events in solidity are a way to inform the calling application about the current state of the contract. Like notifying the javascript client about a change made to the contract allowing the client application to react to it.

Events are defined within the contract as a global and are called from inside a function. To declare an event you use the `event` keyword, followed by an identifier and the parameter list. The values passed to the parameters are then used to log the information that is saved as part of the transaction inside the block.

To send the event you'll use the `emit` keyword from anywhere inside the contract by passing the name of the event and the corresponding parameters.

For this contract you want to let the client application to know when a tip was successfully sent. To do that you'll create a new event named `NewTip` like this

```javascript
event NewTip(address indexed from, string message, string name, uint256 amount);
```

It will accept an address to identify who sent the tip, the message of the tip and also the name and the amount of eth sent,

And then, it will be emitted from the `sendTip` function

```javascript
// send the event
emit NewTip(msg.sender, _message, _name, msg.value);
```

This event will use the same parameters that the rest of the `sendTip` operation.

- `msg.sender` to get the address of who sent the tip
- `_message` the string with the message sent
- `_name` the name of the sender
- `msg.value` the amount of `eth` sent.

Add eth Withdraw Functionality in a Smart Contract and Emit Solidity Events

In this lesson, you'll discover how to style View Transitions using CSS pseudo-selectors to create custom animation effects. We'll transform the default cross-fade into a smooth slide transition by targeting the ::view-transition-old and ::view-transition-new pseudo-elements. You'll learn how these powerful selectors give you precise control over your transition animations, allowing you to create more engaging and personalized user experiences with just a few lines of CSS.

Customize View Transitions with CSS Using view-transition-old and view-transition-new

In this lesson, you'll learn how to implement smooth state transitions in your web applications using the browser's built-in View Transitions API. We'll create a simple example that demonstrates how to animate between different text states with just a few lines of code - no external libraries required. This powerful native API makes it easy to add professional-looking transitions to your user interface, enhancing the user experience with minimal effort.

Create Smooth UI Transitions with the Native View Transitions API

I've been using Cursor for a very long time and their "Agent" feature in Composer is fairly new, so I'm still getting used to it. But since Windsurf recently got onto the stage with their Cascade agent, they've slowly been gaining the mind share on the UX for coding agents. I decided to put them to the test by putting Windsurf and Cursor on the exact same screen side by side trying to accomplish the same task and to see which workflow I would prefer. I've been a diehard Cursor user for over a year now, so it's going to take a lot for me to switch to a different IDE. But I just have to say, even from this simple demo, Windsurf is looking pretty nice.

This lesson is just going to walk through creating a CLI using both tools to print out inspirational quotes and to explore how they approach the step-by-step of installing packages and running commands and setting up all the files we need to get this running.

Windsurf Cascade vs. Cursor Composer Agent Side-by-Side Comparison

This TypeScript tutorial explains how to use generics, allowing for different types to be passed as arguments. It discusses the use of shorthand syntax in generics and illustrates with examples. This method is useful for library creation, providing type safety and control to the user.

```typescript
interface PhotoMetadata<T> {
  title: string;
  takenAt: Date;
  customData: T;
}

// Function that processes a photo with custom metadata
function processPhoto<T>(photo: PhotoMetadata<T>): {
  processedTitle: string;
  daysSinceCapture: number;
  customDataSummary: T;
} {
  const today = new Date();
  const daysSinceCapture = Math.floor(
    (today.getTime() - photo.takenAt.getTime()) / (1000 * 60 * 60 * 24)
  );

  return {
    processedTitle: photo.title.toUpperCase(),
    daysSinceCapture,
    customDataSummary: photo.customData
  };
}

// Example usage with different custom data shapes
type CameraSettings = {
  iso: number;
  aperture: string;
  shutterSpeed: string;
}

type LocationData = {
  latitude: number;
  longitude: number;
  locationName: string;
}

// Using with camera settings
const photoWithCamera: PhotoMetadata<CameraSettings> = {
  title: "Sunset at beach",
  takenAt: new Date('2024-01-15'),
  customData: {
    iso: 100,
    aperture: "f/2.8",
    shutterSpeed: "1/1000"
  }
};

// Using with location data
const photoWithLocation: PhotoMetadata<LocationData> = {
  title: "Mountain vista",
  takenAt: new Date('2024-02-01'),
  customData: {
    latitude: 45.5231,
    longitude: -122.6765,
    locationName: "Mount Hood"
  }
};

const processedCameraPhoto = processPhoto(photoWithCamera);
const processedLocationPhoto = processPhoto(photoWithLocation);

processedCameraPhoto.customDataSummary.iso
processedLocationPhoto.customDataSummary.longitude

```

Basic Explanation of Typescript Generics

A very basic explanation of generic function arguments

I've been using Cursor as my primary editor for over a year now, but recently I've heard wonderful things about Windsurf AI Agent features. I decided to record myself building out something I've always wanted to make, but never made the time for.

In this lesson, I demonstrate how to leverage Windsurf's powerful agent process to create a fun word-guessing game inspired by Heads Up. Watch as I build an interactive application featuring category selection and word navigation, complete with data hosting on GitHub Gists and deployment to GitHub Pages - all in under 30 minutes (before editing the lesson down to 12 minutes)!

What makes this project particularly exciting is how Windsurf eliminates the typical friction points of development. While this game was always on my project wishlist, the overhead of setup, configuration, and deployment made it hard to justify the time investment. Windsurf's agent process handles all these pain points seamlessly, from managing URLs to orchestrating deployment.

This lesson perfectly showcases how AI agents can help developers bring their backlog of project ideas to life, transforming what would typically be time-consuming tasks into efficient, enjoyable development experiences.

Build a Word Game with Windsurf's Cascade AI Agent



Discover how to harness the power of Cursor IDE's Composer Agent feature to optimize your code. In this lesson, you'll witness an AI agent doing all the work to generate test suites, implement performance benchmarks, and create optimized function variations - all without writing a single line of code. You'll learn how to validate performance improvements through data-driven benchmarking, ensuring that optimizations are backed by concrete metrics rather than speculation. This hands-on demonstration showcases a groundbreaking approach to automated function development that combines the precision of test-driven development with the efficiency of AI-powered optimization.


Agent-Driven Development in Cursor: Testing, Benchmarking, and Optimizing Functions

This course is aimed for using `zod` effectively in projects based on TypeScript (both browser and node.js). The benefits you gain with this course is not just simply coding, but also understanding when/why/how should you perform runtime validation.

`zod` is the missing piece to TypeScript's capabilities, which can guarantee type-safety only in compile-time.

`zod` can be used whenever the compiler cannot guarantee what happens in runtime. And... it's a very frequent usecase, such as HTTP calls, websockets, etc.

In this course you get quickly up and running by:
1. using `zod` with primitives and objects
2. adapting `zod` quickly to existing projects thanks to automatic generators
3. changing the strategy frm type-first to schema-first
4. using error-throwing `parse` or non-error-throwing `safeParse` basing on your needs
5. applying `zod` to the most common usecase - validating API responses
6. handling errors the most convenient way (out of many!)

Take advantage of runtime validation with `zod`. Take advantage of the detailed lessons in this course 🔥

Effective Runtime Type Checks with Zod


Cursor can now automatically run commands in the terminal and walk step-by-step towards building out your entire project. You give it a goal, then it will suggest the commands you need to run and the files that you need to create and you can work with it to achieve what you're building. This lesson does a quick walkthough of using a Cursor Agent to build a project from scratch and guide it along the way. Cursor Agents definitely feel like a sneak peek at the future of programming!

Cursor Agents Initial Impressions - Allow an AI to Build Your Entire Project

Mock Service Worker is an API mocking library that allows you to write client-agnostic mocks and reuse them across any frameworks, tools, and environments.



Mocking WebSocket APIs with Mock Service Worker


While using anonymous functions might seem convenient, they can create difficulties when trying to identify performance bottlenecks during profiling. This lesson will demonstrate how named functions make it easier to pinpoint and address performance issues, ultimately leading to more efficient and debuggable code. Learning this practice will greatly improve your ability to locate and fix performance issues in complex projects.

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