Learn Chai, Chrome and Mac

“a11y” stands for “accessibility.” It is a numeronym, with 11 representing the count of letters between the letter a and the letter y.

Accessibility is broken down into 4 categories of disability: visual, cognitive, auditory, motor. 

Regardless of the category of disability, accessibilities aim in web development is to make applications and websites usable for everyone.

a11y

To audit our app for accessibility issues at runtime we can use Cypress to run our application in a browser environment and then with the aid of the axe-core `cypress-axe` library we can analyze the current page for any accessibility issues.

## Resources
* https://www.cypress.io/
* https://github.com/component-driven/cypress-axe
* https://mochajs.org/#bdd
* https://www.chaijs.com/guide/styles/

Write E2E Tests for Accessibility Using aXe-core and Cypress

JavaScript® (often shortened to JS) is a lightweight, interpreted, object-oriented language with first-class functions, most known as the scripting language for Web pages, but used in many non-browser environments as well such as node.js or Apache CouchDB. It is a prototype-based, multi-paradigm scripting language that is dynamic, and supports object-oriented, imperative, and functional programming styles.

javascript

To audit our app for accessibility issues at runtime we can use Selenium WebDriver to run our application in a browser environment and then with the aid of the aXe-core `webdriverjs` library we can analyze the current page for any accessibility issues.

## Resources
* https://www.selenium.dev/documentation/getting_started/installing_browser_drivers/
* https://github.com/dequelabs/axe-core-npm/blob/develop/packages/webdriverjs/README.md 

Test Accessibility at Runtime with Selenium WebDriver and aXe-Core

React is one of the web’s most popular frameworks for building JavaScript applications. 

If you know what you’re doing, React can drastically simplify how you build, use, and maintain code.

Whether you’re a React newbie or you’re ready for advanced techniques, you can level-up with egghead. Explore our in-depth courses, lessons, and community resources to build more powerful applications and crack open your career.

react

In this lesson we install the [Redux Dev Tools](https://github.com/zalmoxisus/redux-devtools-extension#installation) extension into Chrome and demonstrate how it lets you inspect the various actions passing through your redux store as well as all of the data it contains. We also briefly demonstrate the time travel debugging capability as we walk back through and un-add items to our shopping cart.

The key here is that because we used [configureStore](https://redux-toolkit.js.org/api/configureStore) from RTK which automatically includes support for redux dev tool without having to explicitly turn it on.

Using the Redux DevTool Support Built-in to Redux Toolkit

Cascading Style Sheets bring order and beauty to our applications.

In this lesson, we take a look at how to animate and transition custom properties with CSS Houdini @property. It hasn't been possible to animate and transition background-images and other properties until now. This demo will show you how to define custom properties and define type checking for them.

Check for [Browser Compatibility](https://caniuse.com/mdn-css_at-rules_property).

Use CSS @property to Animate and Transition Custom Properties

In this lesson, we take a look at the CSS aspect-ratio property and see how we can define different aspect ratios for elements.

Check for [browser compatibility](https://caniuse.com/mdn-css_properties_aspect-ratio).

Use CSS aspect-ratio to prescribe an aspect ratio for an element

CSS Media queries are heavily used across web pages for different reasons, such as make your web pages responsive, but what if we can use them to improve web accessibility as well?

In this video, I’m sharing How to use CSS Media Queries for web accessibility in your web app, combining the user preferences choice with `prefers-color-scheme` media query and enabling dark mode in your web app.

Create a Dark Mode Theme in Your Web App Using CSS Media Query

Optional chaining ?. in javascript is a new feature introduced in ES2020. Optional chaining changes the way properties are accessed from deeply nested objects. It fixes the problem of having to do multiple null checks when accessing long chain of object properties in javascript.

Optional Chaining

The Chrome Developer Tools (DevTools for short), are a set of web authoring and debugging tools built into Google Chrome.

chrome-devtools

Lighthouse is a tool that analyses web apps and web pages, collecting modern performance metrics and insights on developer best practices.

It's built directly into the Chrome DevTools and in this quick lesson we're going to learn how to run the audit, how to read its results and why you should always run the Lighthouse audit in Incognito mode.



Run a Lighthouse audit in Chrome Devtools

Sometimes you encounter a backend issue which seems to occur only on your computer, with a very specific sets of headers, cookies etc. Because of that, it's useful to have a way of easily sharing network requests sent by your browser with other members of your team.

In this quick lesson we're going to learn how to copy a network request as `fetch` (so we can test it in the Chrome DevTools console/in a node.js script) or as cURL (so we can test it in a terminal).

Copy a network request as fetch or cURL with Chrome DevTools

Sometimes when debugging our CSS styles it's useful to be able to see what a DOM element is going to look like in a given state (e.g. `:focus`, `:active, `:hover`) etc.

Unfortunately it's not possible to both hover over an element and debug it in Chrome DevTools at the same time (since we only have a single cursor!).

In this quick lesson we're going to learn how to address this problem by explicitly forcing an element state to `:hover` with DevTools

Force a DOM element state in Chrome DevTools

Switching project contexts causes needless friction and opportunities for distraction as we try to pull up related tabs and applications. I learned a trick from [David Sparks](https://www.macsparky.com/) on how to use the Mac automation software [Keyboard Maestro](https://www.keyboardmaestro.com/main/) to create palettes of shortcuts grouped by context. This has been an awesome boost to my productivity!

Seamlessly Switch Project Contexts with Keyboard Maestro

In this lesson, we look at how you can use `content-visibility: auto` to significantly improve page load performance by applying it to `section` elements. The property tells the browser to skip rendering an element if it is off-screen and below the fold on the initial load. 

This can introduce some scroll jumping which we walk through how to combat with `contain-intrinsic-size`.

• Read more about `content-visibility` and `contain-intrinsic-size` here: https://web.dev/content-visibility/

Use content-visibility: auto to Improve Initial Page Load Time

Check out the new and currently experimental "CSS Overview" feature in Chrome's DevTools.

Use it to get an overview of details such as colors, fonts, media queries, and even unused declarations.

Explore a Site's CSS with Chrome DevTools CSS Overview

PostgreSQL is a powerful, open source object-relational database system.

postgres

YugabyteDB is an open source, high-performance distributed SQL database for powering global, internet-scale applications.YugabyteDB is also a cloud-native database, so it can be deployed across both public and private clouds, including  Kubernetes environments. In regards to serving as a backend for microservices, YugabyteDB brings together three must-haves: a PostgreSQL-compatible SQL API, low-latency read performance, and globally distributed write scalability. YugabyteDB with its global data distribution brings data close to users for multi-region and multi-cloud deployments. 

In this lesson we will see how we can create YugabyteDB cluster locally on our Mac for dev environment and prototyping 

Set up YugabyteDB Distributed SQL Cluster Locally on MacOS

In this lesson we will see how to measure the used JS heap size in chrome. This can be used for various needs from performance debugging to production monitoring of apps.

Measuring used JS heap size in chrome

Providing real time information to your Javascript apps with [ASP.NET Core SignalR](https://www.npmjs.com/package/@microsoft/signalr). With ASP.NET Core and SignalR you can add real time functionality with ease and keep your application up to date without letting the clients reloading their page manually.

Expose Values for Real-time Consumption with SignalR in ASP.NET Core

In this video, we'll learn how to modify the default screenshot keyboard shortcut on macOS so that it copies our screenshot to our clipboard. This comes in handy if you share screenshots often.

Change Default Screenshot Key to Copy to Clipboard

Joe Previte is an active egghead instructor and blogger. This is a collection of screencast versions of selected blog posts. You can find his blog here: [joeprevite.com](https://joeprevite.com/)

Joe's Blog Posts as Screencasts

The pluggable linting utility for JavaScript and JSX.

eslint

We have a number of options to use when testing for accessibility issues concerning alternative text for images.  The react-axe library and axe browser extension will both report when an image is missing alternative text.  The tota11y browser extension will annotate any images that are missing alternative text.  Running eslint with the eslint-plugin-jsx-a11y plugin installed will report on any `<img>` elements missing an `alt` attribute.  Finally, we can use a screen reader to actually hear what is read when an image has focus.

Test for Image Alternative Text Accessibility Issues

Images must have text alternatives that describe the information or function 
represented by them so they can be read and understood by those using screen readers.

## Alternative text for images
* All `<img>` elements should have an `alt` attribute provided
    * When not provided many screen readers will fallback to reading the file name instead
* The `alt` value should not include words like _“image”_, _“picture”_ or _“icon”_
    * Screen readers are already announcing that the element is an image
* Images that are decorative only and provide no information or function to the page should be hidden from Assistive Technologies by providing an empty `alt` attribute (`alt=””`)

## References
* https://www.w3.org/WAI/tutorials/images/
* https://www.w3.org/WAI/tutorials/images/decision-tree/
* https://www.w3.org/WAI/tutorials/images/tips/
* https://www.w3.org/WAI/tutorials/images/informative/
* https://www.w3.org/WAI/tutorials/images/functional/
* https://www.w3.org/WAI/tutorials/images/textual/

Define Images with Appropriate Text Alternatives

Just about every tool in our accessibility auditing toolkit can help us identify any issues with sufficient color contrast ratio on a web page.  The react-axe library and axe browser extension both report findings on all elements with insufficient contrast ratios.  The tota11y browser extension will annotate any elements with their contrast ratios and color those that are insufficient in red.  

Additionally, we need to use our experience tools to see what some of our users out there may we seeing.  We need to test with high contrast browser extensions as well as the display settings in Windows and Mac.  If our users with visual impairments are using these tools we need to see what our application looks like using them because we may find that under a certain mode some things may suddenly be harder to read or virtually invisible.

## Resources
* https://www.scottohara.me/blog/2019/02/12/high-contrast-aria-and-images.html

Test for Insufficient Color Contrast Accessibility Issues

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.

Always Name Functions in JavaScript


When attempting to load the same module twice in JavaScript you'll hit a cache and code won't re-run. In scenarios where you actually do want to have state in your modules, you'll have to use a cache-busting technique by passing a query parameter to a dynamic import. This lesson walks through how to add a query parameter, how to add the appropriate types for loading dynamic modules in TypeScript, and when these techniques are valuable.

Import the Same JavaScript Module Multiple Times with Cache Busting



The include keyword in GitHub Actions empowers you to add custom variables to your matrix strategy, providing flexibility beyond standard configurations. In this video, we'll explore how include allows you to define specific combinations of variables, enhancing control over your workflow runs. You'll see how this feature enables you to tailor jobs for unique environments or scenarios not covered by the default matrix options. By leveraging include, you can efficiently manage complex build processes with greater precision. This technique helps you streamline your CI/CD pipeline, making it more adaptable to your project's evolving needs.

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