Learn Eslint, Hapi and Tweenlite

hapi is a battle-tested, full-featured, framework for building web applications and services with Node.js. With integrated support for essentials like authentication, caching and validation, and a powerful plugin system, hapi is ideal for projects and teams of any size.

This course will introduce hapi, some of it’s plugins, and guide you through many of hapi’s core features.

A rich framework for building applications and services hapi enables developers to focus on writing reusable application logic instead of spending time building infrastructure.

hapi

Introduction to Node Servers with Hapi.js

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

Our first layer of defense when building accessible React applications is to add some auditing tools to our development workflow. This should include adding static analysis checking for common accessibility standards and best practices. We can get this with the latest eslint plugin: "eslint-plugin-jsx-a11y". If you are already linting your projects adding this plugin should fit very smoothly into your workflow.

## Resources
1. [List of all the rules supported by eslint-plugin-jsx-a11y](https://github.com/evcohen/eslint-plugin-jsx-a11y#supported-rules)
2. [Comparison of the difference in rules between recommended and strict mode](https://github.com/evcohen/eslint-plugin-jsx-a11y#difference-between-recommended-and-strict-mode)
3. [Background on how the Accessibility API implemented by browsers interfaces with Assistive Technologies](https://github.com/evcohen/eslint-plugin-jsx-a11y#some-background-on-wai-aria-the-ax-tree-and-browsers)

Set up ESLint to Audit Accessibility Issues in React

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

Our accessibility auditing toolkit makes it very easy for us to test for any form controls that are missing labels or are not correctly associated with their labels.  Running Eslint with the eslint-plugin-jsx-a11y installed will show us any form controls with missing or unassociated labels.  Running react-axe or using axe to audit a web page will similarly list any of these findings.  Finally using tota11y we can annotate any form controls on a page that are missing labels.  This is definitely some of the lower hanging fruit that we can easily find and fix when making our applications accessible!

Test for Form Control Label Accessibility Issues

Labeling inputs, elements, and widgets add context and clarity for assistive technology such as screen readers.  Elements of a `<form>` such as `<input>` or `<textarea>` or `<select>` should be labelled by using a `<label>` element.  Placeholder text can be used in addition to a label but should not be used in place of a label as not all assistive technologies respect placeholder text.

Ensure Form Controls have Accessible Labels

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

In this lesson you will learn how to use the eslint yeoman generator to scaffold a new plugin to provide custom rules for your project. 
You will also be able to check the basic skeleton for an eslint ruleand a working example rule to apply a naming convention for async functions.

Scaffold an eslint Plugin with Yeoman

Nx already comes with a default TypeScript setup. Although you can opt-out of that and generate plain JS based components, especially in a large setup TypeScript can be beneficial in uncovering potential issues early. To add an extra level, Nx also comes with preconfigured eslint for all the apps and libraries. In this lesson we're going to explore the lint setup and how it can be used.

Linting a React app with Nx

View engines, or template engines, allow you to maintain a clean separation between your presentation layer and the rest of your application. This video will demonstrate how to use the vision plugin with hapi to enable template support.

hapi.js - View engines 

hapi does not support serving static files out of the box. Instead it relies on a module called Inert. This lesson will cover serving static files using Inert's custom handlers.

hapi.js - Serving static files

Routing is a fundamental aspect of any framework. In this lesson, you'll learn how to use path parameters in hapi's router. We'll also touch on how the router uses specificity to order routes internally.

hapi.js - Route parameters

hapi doesn't ship with logging support baked in. Luckily, hapi's rich plugin ecosystem includes everything needed to configure logging for your application. This video will introduce good, a process monitor for hapi, and good-console, a reporter for good that outputs to standard out.

hapi.js - Logging with good and good-console

hapi makes handling POST and PUT payloads easy by buffering and parsing them automatically without requiring additional modules or middleware. This video will demonstrate how to handle JSON and form based request payloads via hapi's route configuration.

hapi.js - POST and PUT request payloads

hapi's reply interface is one of it's most powerful features. It's smart enough to detect and serialize objects, buffers, promises and even streams. This video will demonstrate first hand how to use the reply method to send your data to the client, no matter the format.

hapi.js - Replying to Requests

Think of hapi's `reply()` function as "what you want to say" and the `response` object as "how you want to say it". While `reply` controls the payload sent to the client, the `response` object will allow you to control how the client interprets the payload by manipulating status code, content type, state and more.

hapi.js - Using the response object

hapi automatically responds with JSON for any error passed to a route's `reply()` method. But what if your application needs errors rendered in HTML? This lesson shows how to implement friendly HTML error messages using hapi extension events.

hapi.js - Friendly error pages with extension events

hapi supports request validation out of the box using the joi module. Request path parameters, payloads, and querystring parameters can be validated with joi's simple, yet powerful, notation. This lesson covers the basics of validating requests using joi.

hapi.js - Request Validation with Joi

hapi has built-in support for parsing cookies from a request headers, and writing cookies to a response, making state management easy and straight-forward. It even has built in support for cookie encryption and auto detects when a cookie contains JSON, parsing or stringifying automatically.

hapi.js - Managing State with Cookies

hapi is a rock solid server framework for Node.js. Its focus on modularity and configuration-over-convention makes it the perfect match for any size development team. This video will introduce you to hapi by showing you the bare minimum needed to run a hapi server.

hapi.js - Up and running

ESLint is a JavaScript linter (static analysis tool) that offers full support for ES6, JSX, and other modern tools via plugins. We walk through setting up ESLint in a project, using the `eslint --init` CLI tool with the JSX and ES6 options, writing a React component in JSX, and adding some extra react linting rules with a plugin. ESLint is built to be "pluggable" with simple, extendable, modular rules and an API for writing and using plugins. ESLint has many rules which are all turned off by default; you can extend the core "recommended" rules which will catch common JavaScript errors, and you can also turn on stylistic rules for code consistency. You can also use plugin rules which we do in this lesson with the `eslint-plugin-react` package.

Linting React JSX with ESLint (in ES6)

Instead of using middlware, hapi provides a number of points during the lifecycle of a request that you can hook-in to provide additional functionality, called "extension events". This lesson will give you an introduction to using extension events, and show how they can be used to manipulate the request or response in-flight.

Topics

Instructors

Content Type

Free or Pro