Learn Flexbox, Puppeteer and Screen-reader

It's tempting to pick up a framework which has preselected flexbox or grid as the layout tool of choice, but it's important to learn when and why to use each method. This leads to slimmer stylesheets which results in better site performance, and less likelihood for "hacks" to make one method do what the other does inherently better. 

Throughout this collection, we will be progressively styling a responsive landing page template while building your knowledge on when to select grid or flexbox for any layout scenario. Spoiler alert: sometimes the best solution is using both!

The specification describes a CSS box model optimized for user interface design. In the flex layout model, the children of a flex container can be laid out in any direction, and can “flex” their sizes, either growing to fill unused space or shrinking to avoid overflowing the parent.

flexbox

Create a Landing Page with CSS Grid and Flexbox

OpenGraph images are the images you see when you paste a link into a social platform and it "unfurls" into an image, title, and description. This happens on Twitter, Discord, Slack, and many other platforms. This collection goes over everything from designing OpenGraph images in Figma, to implementing them in CodeSandbox, to returning headless browser screenshots from Netlify Functions, and finally using Cloudinary as a write-through cache. 

You will come away from this collection with the ability to ship an API that you can use on any of your sites, and also on-demand, that can generate images for not only OpenGraph unfurls, but also for Instagram, GitHub, and more. Using headless browsers with playwright to generate our images means we get full access to all the responsive power of CSS and all the logical power of JS to handle layout, importing assets like pngs, choosing different fonts, and more.

The image below is generated via the project you'll build and deploy in this course

![An example opengraph image](https://relaxed-payne-d1bfbe.netlify.com/opengraph?title=Building%20an%20OpenGraph%20image%20generation%20API%20with%20Cloudinary%20Netlify%20Functions%20and%20React&tags=figma,netlify%20functions,playwright&author=chrisbiscardi)

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

Building an OpenGraph image generation API with Cloudinary, Netlify Functions, and React

A large number of people are unable to use the web effectively due to an impairment or disability.

As developers there are several tools and techniques we can use to make our web applications accessible, ensuring a great user experience that includes everyone.

We all agree that Accessibility is important. However, it’s a broad landscape and can be overwhelming figuring out where to start!

Erin Doyle is an expert in creating accessible React applications and has developed a course that will give you a concrete process for testing, refactoring, and building your applications with accessibility in mind.

After this course, you'll have a jump start on auditing and fixing accessibility issues in your applications and gain a better understanding of your target users and how to approach your web app design from their perspectives.


Develop Accessible Web Apps with React

Flexbox is a powerful way to layout HTML so that elements can grow to fit the size of their container.  It can also control how the elements are positioned within a flexed container.  

Once you start thinking in `rows` and `columns`, you can control almost any flexed layout with just a few simple flexbox layout primitives.

Get Started with Flexbox CSS Layouts

Flexbox is a wonderful tool built into the CSS specification. Using flexbox doesn't require any special framework or library, just a browser with CSS3 support. It is so awesome, and makes the arranging elements on a page almost fun!

Flexbox Fundamentals

Demystifying alignment in flexbox children

Flexbox makes it easier to create layouts that can adjust depending on the content that is added and the space available. In this lesson we look at a couple real-world applications of Flexbox in an application and website.

Using Flexbox in Websites and Applications

The flex-basis property allows us to define the dimension (along the flex-direction axis) that a flexbox child should ideally have.

Defining dimensions on flexbox children using flex-basis

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

Flex-basis lets us set the ideal dimensions for a flexbox child, but flex-shrink lets us define what should happen if there isn't enough room, and flex-grow can define what happens when there is too much room.

Using flex-shrink and flex-grow to make flexbox children resize correctly

Using the `order` property we alter the order in which flexbox children appear on the page, without making changes to the dom.

Using order to rearrange flexbox children

The flex shorthand makes it easier to declare flex-shrink, flex-grow, and flex-basis, but it sometimes has unexpected results because the defaults differ.

Combining the flexbox sizing properties using the flex shorthand

The Flexbox css spec allows for more adjustable layouts. The `flex-direction` property allows you to easily change the layout on the children of an element without making any changes to the dom, which is particularly useful when combined with media queries.

Using flex-direction to layout content horizontally and vertically

Adding flex-wrap to a flexbox container allows the items to form a grid. The content can then be aligned and distributed along the grid using justify-content and align-content.

Turning a flexbox into a grid using flex-wrap and align-content

React Native lets you build mobile apps using only JavaScript. It uses the same design as React, letting you compose a rich mobile UI from declarative components.

react-native

React Native utilizes flexbox for layout, and you can apply styles inline, or via external stylesheets. We will learn about both approaches, and create some basic styles for a native application.

For getting your application setup, you might want to checkout [this lesson](https://egghead.io/lessons/react-react-native-up-and-running?course=react-native-fundamentals&from=react-applying-styles-in-react-native)

Applying Basic Styles in React Native

Puppeteer is a Node library which provides a high-level API to control headless Chrome or Chromium over the DevTools Protocol. It can also be configured to use full (non-headless) Chrome or Chromium.

puppeteer

In this lesson we are going to send commands to the chromium browser with Puppeteer. These commands will enable us to calculate both the total number of CSS stylesheets used on the page and the ruleUsage for each of those stylesheets. With these metrics we will be able to calculate the percentage of unused CSS on the page. 

Get the Percentage of Unused CSS on a Page with Google's Puppeteer

In this lesson we are going to use the firstPaintTime metric from chrome's load times, as well as the navigation start from the W3C window metrics, to calculate how long it takes a page to paint. We will set up a quick function and test it out on google.com

Calculate a Page's First Paint Time with Puppeteer

In this lesson we are going to use Google's Puppeteer to gather metrics about a page's load time. We'll use a high level date subtraction method as well as gather data from the window performance timing. Then see how throttling the network to 3G affects the page's load time. 

Get a Page's Load Time with Puppeteer

It can be helpful when automating tests, metrics, and integration tools to know not only how much JavaScript there is on a page but to calculate how much is not being used. We are able to calculate the percentage of JS used by getting metrics from the window object. 

Get the Percentage of Unused JS on a page with Puppeteer

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?

After setting `display: flex` on a parent element, you can use `flex-direction` to switch the container to be either a `row` or a `column`.

We also switch the body between `row` and `column`.

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