Learn Eslint, Ios and Particle

A lot of the time, web apps are built primarily with the desktop layout in consideration, and the mobile layout suffers as a result. In this course we are going to discuss using features of user interface which are optimised for mobile devices.

We are going to discuss CSS features that make a big difference and build entire components that work great on mobile devices and browsers. We are going to take into account browser support to ensure our users are getting the experience we want them to.

More and more of our users depend on their mobile device to use our web apps. With this in mind, we are going to look at how to optimise the components we build for smaller viewports, and how to ensure our customer gets an optimised version of our web app for their device.

We are going to discuss different ways we can view, test, and debug our web app in a mobile setting so that we know what we are seeing is what our user is seeing, because sometimes a desktop browser emulating a mobile device just isn’t enough.


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

html

Optimize User Experience for Mobile Devices and Browsers

Open source framework for building truly native mobile apps with Angular, TypeScript or JavaScript.

nativescript

We will learn how to install an Objective C library distributed via a [CocoaPod](https://cocoapods.org) into our project and expose its native api to our app. Specifically, we will cover how to immediately start working with the library even when a [NativeScript](/q/nativescript) plugin does not exist for it. Take for example [Filestack](https://filestack.com), a really powerful file uploading api that provides an SDK written in [JavaScript](/q/javascript) for the web, but also offers native SDK's for iOS and Android. Let's take a look at how to code right against this [native iOS SDK](https://filestack.com/docs/sdks/ios).

Use an Objective C library in NativeScript for Angular iOS app

Flutter allows you to build beautiful native apps on iOS and Android from a single codebase.

flutter

In this lesson we’ll learn how to style Text & Container widgets & also get a general understanding of how styling works in Flutter applications

Style a Flutter Text and Container Widget

Dart is an open-source, scalable programming language, with robust libraries and runtimes, for building web, server, and mobile apps.

dart

When creating a new Flutter application, you are given a simple templated Flutter project whose primary code lives in the main.dart file. In this lesson, we walk through this file & talk about what the boilerplate code is doing.

Walkthrough of the Default Flutter Application Boilerplate

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

Progressive Web Apps can speed up app loading times, and even allow you to run your web app offline, and install it on a mobile device!  However, setting up a PWA correctly can be tricky.

In this course, we'll create a PWA from start to finish, using create-react-app.  We'll create a custom service worker, and use different caching strategies for different types of assets.

Finally, we'll look at how to install the app on both iOS and Android devices, and how to customize the app name, icon, and splash screen.

Course Introduction: Progressive Web Apps in React with create-react-app

In this lesson we’ll learn how to use themes in order to share colors and font styles throughout our application.

Using Themes in Flutter to Share Colors and Font Styles

In this lesson we’ll learn how to render both local & network images in a Flutter application using the Image class.


Load an Image in a Flutter App with the Image Class

In this lesson we’ll learn about the main layout widgets you'll need when building your user interface in Flutter. We’ll take a look at Container, Center, Row, Column, Stack, & GridView widgets learn how they work.

Building Layouts in Flutter with Layout Widgets

In this lesson we’ll learn how Navigation in Flutter works by navigating to a new page when clicking on a button using the push & pop methods. We'll also look at how to pass properties to a new screen dynamically.

Getting Started with Navigation in Flutter

In this lesson, we'll learn how to specify a configuration object containing all of the routes for our application & navigate between them in a Flutter application.

Navigation with Named Routes in Flutter

ListView is the most commonly used scrolling widget in a Flutter application. In this video, we'll learn how to create dynamic lists using Flutter's ListView widget to render both lists of Strings & lists of Maps

Building Dynamic Lists in Flutter with ListViews

In this lesson we’ll learn how to fetch & then display data from an API over the network in a Flutter application using the http package.

Fetching & Displaying Data from an API in Flutter using the http Package

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

Objective C is a very interesting programming language which offers a lot of power as well as interesting paradigms. Let’s look at some Objective C api’s and how they translate to NativeScript. In particular, let’s learn how to wire up iOS delegates using [Filestack's FSPickerDelegate](https://github.com/filestack/FSPicker#fspickerdelegate) as an example. We will also look at handling WeakRef’s and iterating an NSArray.

Use Objective C Delegates in NativeScript for Angular iOS apps

One of the exciting benefits you have with NativeScript is the ability to write native code (Java and Objective C) directly in JavaScript/TypeScript allowing you to create a consistent high level api over top of both underlying iOS Objective C/Swift and Android Java apis. In this lesson, we will look at how to design a consistent api that taps into the appropriate native api’s on the target platforms using underlying native libraries.

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