 Courses from Marcy Sutton

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

chrome-devtools

What's in a name? In this lesson, I'll explain the concept of naming interactive elements for screen reader users, including forms, buttons, and links. You'll learn how to debug accessible names and descriptions using the Chrome Accessibility Developer Tools (previously a Canary experiment, now in Chrome), using multiple labeling techniques. We'll also listen to the effects of proper accessible names and descriptions in Voiceover and Safari.

For more information and the nitty-gritty browser implementation algorithm, refer to WAI-ARIA 1.1: 
- https://www.w3.org/TR/wai-aria-1.1/#namecalculation
- https://www.w3.org/TR/accname-1.1/

What is Accessible Name Calculation?

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

Animations can make people sick, or worse! By adding animation toggles and listening in to the user's system preference for reducing motion on OSX and iOS, we can give them more control over our interfaces. Animation can be a safety issue; let's do something about it!

Warning: there is a flashing animation in the video.

In this lesson:
- [prefers-reduced-motion](https://webkit.org/blog/7551/responsive-design-for-motion/)

WCAG 2.1, Guideline 2.3: Seizure risks
- https://www.w3.org/WAI/WCAG21/quickref/?versions=2.0#qr-seizure-does-not-violate

Your Interactive Makes Me Sick
- https://source.opennews.org/articles/motion-sick/

Accessible animations with reduced motion

Testing for accessibility is easy with automated tools like axe-cli. This command-line tool utilizes the open source axe-core JavaScript library to run an audit on any webpage you give it, returning a set of JSON results you can use in your continuous integration environment or regular development workflow. 

- [axe-cli](https://github.com/dequelabs/axe-cli)
- [axe-core](https://https://github.com/dequelabs/axe-core)
- [aXe Chrome](https://chrome.google.com/webstore/detail/axe/lhdoppojpmngadmnindnejefpokejbdd?hl=en-US)

Accessibility testing with axe-cli

Learn the basics of web accessibility testing using the keyboard, [Web Developer Toolbar](https://addons.mozilla.org/en-US/firefox/addon/web-developer/), [aXe Firefox extension](https://addons.mozilla.org/en-us/firefox/addon/axe-devtools/), and Lea Verou's [Contrast Ratio](http://leaverou.github.io/contrast-ratio/) tool. We'll look at how to get an overview of a webpage's accessibility, with special attention paid to solving color contrast issues.

For more on accessibility auditing, check out this article: https://marcysutton.com/how-i-audit-a-website-for-accessibility/

Basic accessibility testing

HTML 5 is the structure of our web pages. It is the markup that represents the DOM (document object model).

html

You can make any element keyboard interactive with the [HTML tabindex attribute](https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/tabindex). But you might need a little extra JavaScript and [ARIA](https://egghead.io/lessons/html-5-intro-to-aria) to support keyboards and screen readers. For more on using tabindex in practice, check out my [focus management](https://egghead.io/forums/1/topics/focus-management-using-css-html-and-javascript) lesson.

Using the tabindex attribute for keyboard accessibility

Learn how to create a modal dialog with accessible keyboard and screen reader mechanics using the native HTML5 dialog element and experimental inert attribute (with polyfills) and JavaScript focus management. We'll explore how to make a DIV or non-modal dialog into a modal one to contrast the differences. Finally, we'll expose accessibility information for NVDA, Voiceover, JAWS and other screen readers.

For more details on creating accessible dialog content, check out this great article by Marco Zehe, Advanced ARIA Tip #2: Accessible Modal Dialogs: https://www.marcozehe.de/2015/02/05/advanced-aria-tip-2-accessible-modal-dialogs/

### Used in this lesson:
- Google dialog element polyfill: https://github.com/GoogleChrome/dialog-polyfill
- Inert attribute polyfill: https://github.com/WICG/inert

Accessible modal dialogs

Cascading Style Sheets bring order and beauty to our applications.

Skip links are an extremely helpful navigation pattern for keyboard and screen reader users, since they let you skip past sections of content. Learn how to create skip links in HTML and CSS that show on focus, and you'll benefit all users!

Creating visual skip links in HTML and CSS

NVDA (NonVisual Desktop Access) is a free “screen reader” which enables blind and vision impaired people to use computers.

nvda

NVDA is a popular open source screen reader on Windows that works well with Firefox. It's similar to JAWS, another popular Windows screen reader that works best with IE. But NVDA has no licensing fee plus an open bug tracker, making it great for users as well as developer testing. 

In this lesson, you'll learn how to browse a webpage using NVDA's keyboard shortcuts, including headings navigation, skip links, and the Elements List. You'll also learn a bit about Forms Mode and how it impacts screen reader navigation.  For more tips, check out the resources below.

## Resources
- [Using NVDA to Emulate Web Accessibility](http://webaim.org/articles/nvda/)
- [NVDA Keyboard Shortcuts](https://dequeuniversity.com/screenreaders/nvda-keyboard-shortcuts)
- [Understanding Screen Reader Interaction Modes](http://tink.uk/understanding-screen-reader-interaction-modes/)
- [Three Things You Should Know Before Using Voiceover for Testing](http://webaim.org/blog/three-things-voiceover/)

## Installing NVDA
If you're on a Windows machine, you can install [NVDA directly](http://www.nvaccess.org/download/). If you're on a Mac or Linux, you could install a Windows virtual machine:

- [Install VirtualBox](https://www.virtualbox.org/wiki/Downloads)
- [Get a Windows VM from Microsoft](https://developer.microsoft.com/en-us/microsoft-edge/tools/vms/) - I use IE11
- [Install Firefox](https://www.mozilla.org/en-US/firefox/new/) - install on the VM!
- [Install NVDA](http://www.nvaccess.org/download/)
- [How to Map Your Mac's Capslock Key to a NVDA or JAWS Key in a Windows VM](https://www.marcozehe.de/2015/06/07/how-to-map-your-macs-capslock-key-to-a-nvda-or-jaws-key-in-a-windows-virtual-machine/)

Testing for Accessibility with the NVDA Screen Reader on Windows

safari

Did you know every Mac comes with a fantastic screen reader built-in? Learn the basics for operating Voiceover with Safari, including common key commands, the web rotor, and the help menu. We'll also set up keyboard tabbing in Safari and OSX's System Preferences, two requirements for accessibility testing that occasionally trip up users. In a future lesson, we'll compare Voiceover to Windows screen readers, since they work quite differently.

#### Resources
- Apple Voiceover commands and gestures: https://www.apple.com/voiceover/info/guide/_1131.html
- WebAIM Voiceover Tutorial: http://webaim.org/articles/voiceover/

Using the Voiceover screen reader to test for accessibility

screen-reader

There are many techniques for hiding content in user interfaces, and not all are created equal! Learn how different hiding techniques in HTML, CSS and ARIA impact keyboard and screen reader users in addition to visual display. As a bonus, we'll also take a look using a screen reader on a mobile device.

How Visible vs. Hidden Elements Affect Keyboard/Screen Reader Users

What is this thing called ARIA? In this lesson, you'll learn about about WAI-ARIA, a.k.a. Accessible Rich Internet Applications, the W3C spec for specifying accessibility information in HTML and SVG. I cover the basics of applying ARIA roles, states and properties, helpful information for creators of user-interface widgets and component libraries. But it's important to note that you might not need ARIA at all! Before using it, it's important to educate yourself on what ARIA does and doesn't do for you.

Intro to ARIA

edge

Coding for accessibility? You should get familiar with the accessibility tree, a structure produced by platform Accessibility APIs running parallel to the DOM, which exposes accessibility information to assistive technologies such as screen readers. There are multiple tools for visualizing this tree; in this lesson we'll look at Chrome and Microsoft Edge. For more on Accessibility APIs, refer to this [amazing article by Leonie Watson](https://www.smashingmagazine.com/2015/03/web-accessibility-with-accessibility-api/). For a how-to on setting up the Chrome Accessibility Inspector, visit [bit.ly/chrome-a11y](http://bit.ly/chrome-a11y).

What is the Accessibility Tree?

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

Something important to consider when coding a web application is managing the user's focus. For keyboard and screen reader users, we must ensure their focus is not dropped as content is deleted or shown in new contexts. Skip links also provide a way for users to get past a lot of content. In this lesson, you'll learn HTML, CSS and JavaScript techniques for focus management that can be applied to many situations.

Focus management using CSS, HTML, and JavaScript

Are you building a website or web application that takes user input? Then it's important for you to watch this demo. Learn how to create more accessible forms using basic HTML form labels, fieldsets and legends. You'll even learn a bit about what makes Safari's developer tools pretty awesome.

Building Forms with Accessibility in Mind

Webpages are more than simply how they look. By coding with headings, landmarks and semantic HTML, you can expose a rich document outline to users of assistive technologies, as well as search engines. 

Headings and semantic structure for accessible web pages

Often buttons need to be handled by JavaScript, and if done improperly it can lead to accessibility issues. In this lesson you will improve a major news organization's global header with some basic HTML and JavaScript.

Accessible Button Events

Accessibility (or a11y) is an important but often neglected in the world of web development. Many developers find themselves coding user interfaces without any knowledge of keyboard or screen reader requirements. 

The fact is that accessibility doesn't happen by accident. Often it is seen as too hard or time consuming. This doesn't have to be the case. By following a handful of high-value patterns and practices, we can open our web apps to humans that otherwise wouldn't be able to interact with them at all.

This course will introduce you to accessibility through hands-on, technical examples that are way more effective than reading 10-year-old static web content.



Start Building Accessible Web Applications Today

Icon buttons are very common in web applications, yet they often have accessibility problems. Learn how to make your icon buttons accessible to keyboard and screen reader users with HTML, CSS, SVG and ARIA.

Accessible Icon Buttons

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.

Use GitHub Actions Matrix Include for Complex Job Configurations

While running `zod` schema validation agains domain-rich objects, the error message saying that _a string is not a number_ might not be really useful.

Especially, when you need to provide a meaningful feeback to the user, e.g. after they have submitted a form with lots of data.

`zod` allows to customize messages on a very granular level. We can also extract repeatable customization to `zod` error maps.

Finally, in order to process an error message further (e.g. display it to the user), we need to handle the `zod` validation errors effectively. Especially, when a big object validation has failed and we could receive a handful of errors.

That's what we learn in this lesson. 🔥

Customize zod Error Messages and Handle zod Errors Effectively

customize zod validation messages, customize zod schema property messages, reuse error maps across different schemas, navigate through zod error objects

You might want to run `zod` schema checks in different styles.

Sometimes you prefer to conditionally throw the error - that's what `parse` does. But another time you'd prefer to receive a `boolean` property that determines whether the validation was successful or not - and perform further actions accordingly.

Additionally, the error-throwing API of `parse` works extremely well with [TypeScript assertion functions](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-7.html#assertion-functions). Their combination is just... perfect! 👌

That's what we learn in this lesson.

Use parse and safeParse Runtime Type-checks with zod

use zod parse function to conditionally throw ZodError, use zod safeParse to get a boolean value and run typescript type guard over success property

In this lesson we learn that TypeScript cannot guarantee correct shapes of responses. That's due to TS performing checks in compile-time, while the response will be availbale in runtime - when TS doesn't exist anymore.

In some situations, such as HTTP requests, runtime type checks such as `zod` are essential for providing quick feedback around data-related errors.

Understand where are the possible mistakes to make while using TypeScript with HTTP calls. Use `fetch` and `axios` along with `zod` schema checks.

Also, note that similar mistakes or mistakes could happen while using web storage (e.g. `localStorage`)

Validate HTTP API Response with zod, fetch and axios

use zod as an HTTP response validation tool along with fetch and axios in order to make sure that the response has expected data structure

In this lesson we learn that the `zod` schemas become the single source of truth.

We shall not update TypeScript types manually, since they are generated automatically from the schema.

Same with validation functions.

Whenever the schema changes, all the rest will update accordingly. It's an important mind shift.

Treat zod Schemas as Single Source of Truth

Zod Schemas are the single source of truth for both typescript types, and interfaces - and runtime validation functions. Schemas should be updated first.

`zod` is powerful, but writing the schemas manually for existing JSON objects, especially big ones, can be time-consuming.

But that's what `quicktype` is for! You can get 80% work done instantly! 🥳

Depending on your need - whether you want to automate the process, or do it just one time, you can:
- use an online app
- use an IDE extension
- run a CLI script
- generate a script to be executed within CI/CD environment/tooling

And this is what we learn in this lesson! 🔥🔥🔥

Get started with zod quickly!

Generate zod Schemas Automatically using Quicktype App, Extensions and Scripts

Use quicktype app, extension or scripts to automatically generate zod schemas from existing json files. Save time and get started with zod quickly!

`zod` is a powerful library allowing to run runtime type-checks.

It's complementary to TypeScript, which does type checks in compile time.

In this lesson we create few schemas that represent primitive type values, along with `zod` utilities which make these more precise. We also create object schemas and nest one inside another.

All schemas are being validated against example values. We analyze how to interpret error messages in case of failures.

Perform Runtime Type-checks on Primitives and Objects with zod

Create zod schemas to validate primitive type and object type values in runtime. Analyze the errors to see how a value doesn't correspond to schema expectations

Marcy Sutton

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