Learn Eslint, Gulp and Nightmare

In this series we will take a look at Gulp. Gulp is a task runner. It is the commander of our army of helper robots that take critical, yet totally mundane, tasks and perform them hundreds of times per day so we don't have to. When we sit down to work, we want to enter a single command, and then spend the rest of our day writing code, testing, and basically not thinking about how it is all glued together in the background.

Automation is critical to any project of significant size. We will start with the Eggly Bookmarks application, and develop proper build automation that will include **production ready** tools that you can start using in your applications today!

AngularJS is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications. Its goal is to augment web-based applications with model–view–controller (MVC) capability, in an effort to make both development and testing easier.

angularjs

Angular Automation with Gulp

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

In this lesson, we are going to learn how to create a config file to store common values so that we can reuse them multiple times in our `gulpfile.js`. As our `gulpfile.js` grows in complexity, we may find that we are introducing complex and multiple file path references. By creating a `gulp.config.js` file, we can simplify these references and make it easier to refactor and extend in the future. 

Angular Automation: Gulp Config

In this lesson, we are going to learn how to use `gulp.watch` to detect local file changes and execute additional Gulp tasks. To illustrate this concept, we are also going to hook up `gulp-jshint` to automation lint our JavaScript as we make changes to our code.

Angular Automation: Gulp Watch

Angular projects require automation. Period. 

In this series we will take a look at Gulp. Gulp is a task runner. It is the commander of our army of helper robots that take critical, yet totally mundane, tasks and perform them hundreds of times per day so we don't have to. When we sit down to work, we want to enter a single command, and then spend the rest of our day writing code, testing, and basically not thinking about how it is all glued together in the background.

Automation is critical to any project of significant size. We will start with the Eggly Bookmarks application, and develop proper build automation that will include **production ready** tools that you can start using in your applications today!

Angular Automation: Introduction to Gulp

In this lesson, we are going to learn how to copy assets from one place to another using Gulp. This is important as you start to prepare your source files to be deployed into production. We will learn how to implement `gulp.src`, `gulp.pipe` and `gulp.dest` as well as the **del** plugin as we copy our files from the source directory into a build directory.

Angular Automation: Copy Assets with Gulp

In this lesson, we are going to learn how to use the `gulp-inject` plugin to sanely and efficiently manage our file references with our HTML. Manually declaring JavaScript references will quickly get out of hand as your application grows in size and complexity. The `gulp-inject` plugin solves this problem by taking a stream of files, converting them into string references and then injecting those references into your HTML via annotations. 

Angular Automation: Gulp Inject

In this lesson, we are going to learn how to automatically serve our project via an HTTP server using `gulp-serve`. Being able to serve our project from an HTTP server allows us to bypass a myriad of development issues such as loading remote source files.

Angular Automation: Gulp Serve

In this lesson, we will learn how tasks work in Gulp. We will talk about how to define a task and what each parameter in the definition does. We will see how task dependencies work and talk about how to handle asynchronous issues using `run-sequence`.

Angular Automation: Gulp Tasks

In this lesson, we learn how to get up and running with Gulp by initializing our project with ```npm init``` and then installing the Gulp CLI globally and then installing it locally to our project. We finish the lesson off by creating our first Gulp file and running our first Gulp task.

Angular Automation: Installing Gulp Globally and Locally

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)

Browserify lets you require('modules') in the browser by bundling up all of your dependencies.

browserify

Building upon the `watch` task that we begin this lesson with, we’ll look at how to create a local development server using the `app` directory as the web root. By using Browsersync to achieve this, we can also instruct all connected browsers to automatically reload each time our bundle is re-generated. Browsersync has a public `.stream()` method that is designed exactly for this purpose.

Gulp and Browserify - Adding Live Reload with Browsersync

Nightmare is a high-level browser automation library.

The goal is to expose just a few simple methods, and have an API that feels synchronous for each block of scripting, rather than deeply nested callbacks. It's designed for automating tasks across sites that don't have APIs.

nightmare

Many pages you'll want to grab data from will require you to log in first. This video demonstrates how to log in and grab whatever data off the page you will need.

Scraping Data from Sites with Login Forms with Nightmare

Gulp is a toolkit for automating painful or time-consuming tasks in your development workflow, so you can stop messing around and build something.

gulp

What is already a nice workflow using Gulp, Browserify, Watchify & Browsersync to enable auto rebuilds & live browser reloading can be further improved by adding Babelify. A simple wrapper around the popular transpiler Babel, Babelify can ‘transform’ source files as they pass through our stream to enable certain Javascript features not yet available in the Browser or Node. We end the lesson by looking at how to generate & extract sourcemaps using `exorcist`.

Gulp and Browserify - Adding Babel & Source Maps

Many websites have more than just simple static content. Dynamic content which is rendered by JavaScript requires browser to be able to scrape data. This video demonstrates how to use Nightmare (which is a wrapper around Electron) to launch a url and scrape dynamic data.

Topics

Instructors

Content Type