Learn Nativescript, Scss and Xstream

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

CSS uses a global namespace for CSS Selectors that can easily result in style conflicts throughout your application when building an application using modern web components. You can avoid this problem by nesting CSS selectors or use a styling convention like BEM but this becomes complicated quickly and won’t scale.

CSS-in-JS avoids these problems entirely by generating unique class names when styles are converted to CSS. This allows you to think about styles on a component level with out worrying about styles defined elsewhere.

In this course, you will learn how to express popular SCSS (Sass) language features using latest JavaScript features. We will convert simple examples from SCSS to CSS-in-JS. As a designer or (S)CSS developer, you should be able to follow without extensive JavaScript knowledge, understanding SCSS is required though. We will not be using any particular CSSinJS libraries. Instead, we will focus on a base knowledge you need later if you use any CSSinJS library.

Sass is the most mature, stable, and powerful professional grade CSS extension language in the world.

scss

Convert SCSS (Sass) to CSS-in-JS

NativeScript has the ability to write Objective C, Swift and Java apis directly from JavaScript and TypeScript. 

In this course, we will learn how to code directly against these native api’s with NativeScript for Angular. Many libraries are written and published in these languages. With NativeScript you are no longer limited to just JavaScript based libs, but have direct access to these api’s right from JavaScript/TypeScript. Let’s look at how to include these native libraries internally to your project as well as build public plugins to share with the community. 

We will cover some considerations with Objective C and Swift based libraries as well as Java/Android libraries. You can think of CocoaPod, Gradle, and Android Arsenal like npm for native libs. iOS libraries can be found via CocoaPods, Android libraries can be found via Gradle or Android Arsenal. 

Let’s also cover how to write custom view components based on native libs since there are considerations for both iOS and Android. Lastly we will learn how to best handle cases where a plugin/library only supports 1 platform.

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

nativescript

Use Objective C, Swift and Java api’s in NativeScript for Angular iOS and Android apps 

Have you ever wished for access to conditionals or iteration when writing styles? How cool would it be to use functions to write styles? SCSS has that and more! SCSS is a superset of CSS. Any valid CSS is SCSS, they even have the same syntax. SCSS borrows features from other languages to write smarter, reusable and more readable styles. This course will focus on how to use SCSS’s more useful features, compare them against each other and assess when their usage is appropriate.

Learn the Best and Most Useful SCSS

In this course, we will learn how to use the core layouts for NativeScript apps. We will start with the basic principles of NativeScript layouts using XML. This course will use the app templates provided from the NativeScript framework and installed using [the NativeScript CLI](https://egghead.io/lessons/angular-1-x-set-up-a-native-app-project-with-the-nativescript-cli).

We will cover the following layouts: `StackLayout`, `WrapLayout`, `GridLayout`, `DockLayout`, `AbsoluteLayout` and `FlexboxLayout`. Understanding the concepts and usage of UI layouts in NativeScript is key for a great app.

Build Basic NativeScript App Templates

In this course, we will learn how to work with NativeScript for Angular. We will start with the basic fundamentals of getting setup to run our app in the iOS Simulator in addition to an Android emulator using GenyMotion (https://www.genymotion.com/). Understand how to build your native mobile views with NativeScript XML and how to style them with CSS. Using the NativeScript for Angular starter template provides a nice setup out of the box including the core theme which provides handy CSS classes to work with speeding up view building. For page navigation, we will learn how to use the Angular Router to configure a flexible routing setup for our app. The ListView component is a powerful and highly performant native control for handling your lists powered by the UITableView on iOS and native ListView widget on Android. We’ll highlight how you can use RxJS Observables with our native views. Let's also take a look at integrating npm plugins to enrich the UI component library. Lastly, a round up of styling how-to's including integrating SASS for custom app theme creation as well as creating a live app theme switcher.

This Angular course assumes a solid understanding of the fundamentals.
We have Intermediary Angular courses including topics on [Dependency Injection](https://egghead.io/courses/angular-dependency-injection-di-explained), [Components, Directives](https://egghead.io/courses/building-angular-components), [Forms](https://egghead.io/courses/intro-to-angular-forms), [Router](https://egghead.io/courses/intro-to-angular-router), and [Animating Web Apps](https://egghead.io/courses/animate-angular-web-applications)

Angular is a development platform for creating applications using modern web standards. Angular includes a wealth of essential features such as mobile gestures, animations, filtering, routing, data binding, security, internationalization, and beautiful UI components. It's extremely modular, lightweight, and easy to learn.

angular

Create Native Mobile Apps with NativeScript for Angular

We will learn how to add an Android library to our project and translate it’s Java api to NativeScript. For this lesson, we will look at [Filestack’s Android SDK](https://github.com/filestack/filepicker-android) built with Gradle. Specifically, we will cover how to immediately start working with the library even when a [NativeScript](/q/nativescript) plugin does not exist for it.

Use an Android library in NativeScript for Angular using Java apis

Learn how to use the `nsRouterLinkActive` directive with options to control styling when a route is active in [NativeScript](/q/nativescript).

Add styles to active routes using nsRouterLinkActive

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

Cascading Style Sheets bring order and beauty to our applications.

In this lesson we'll learn how to convert our Sass code to CSS code. We'll take a look at the sass watch command and use it to listen for changes within our Sass code.

The `sass` executable can be downloaded globally through npm by running `npm i -g sass`.

Converting Sass To CSS

Manage the color palette used in your stylesheets by creating a map of variables and a function to access the values by key. This allows you to update the colors in one location to re-theme your application and eliminate manual find and replace.

Access Theme Color Values With Sass

Learn the fundamental difference between CSS grid and flexbox layout, and create utility classes for each `display` value. Then begin to apply and expand these concepts to style the landing page navigation.

Choose Between Grid or Flexbox for CSS Layout

Apply grid layout and see when it's necessary to break out a media query to overcome grid's lack of wrapping behavior. We'll also learn about a property that grid and flexbox share: `align-items`.

Use CSS Grid to Create Layout Columns

Grid offers us the easiest method to responsively center content. We'll use the grid property `place-content` to center the contents of `figure` to showcase our fictional product in use. Additionally, we'll learn about `object-fit` which is a modern technique that allows inline images to scale responsively within defined dimensions without distortion.

Responsively Center an Image and Caption with CSS Grid

View a preview of the form fields we'll be creating in this course, inclusive of custom CSS styles for text inputs, textareas, selects, multiselects, radio buttons, and checkboxes. Then get an overview of the base project and key parts of the Eleventy build process in regards to compiling with Dart Sass and use of Nunjucks for project template scaffolding. 

Prior experience with Eleventy or Nunjucks is not required, but you may also enjoy learning how to [create an Eleventy site from scratch](https://egghead.io/playlists/build-an-eleventy-11ty-site-from-scratch-bfd3?af=2s65ms) in less than 20 mins in my other egghead collection.

Course Introduction: Accessible Cross-Browser Form Field CSS Styles

We'll define the color palette and create the basic screen styles for our project in addition to Sass helpers for our form design system. 

We will set up Sass variables for the initial them and learn how to use the !default flag to allow our system to be easily overridden from project to project, making our form styles ultra transferable and reusable. You'll also learn how to leverage Sass color functions for ease of theming. We'll map the Sass variables to CSS variables so that as we build up our system we can use CSS variables for the most flexibility in our theming.

Initialize the Form Design System Setup with Sass and CSS Variables

We'll make a starting point for our form layout styles by creating `.form-group` which will add a bit of `margin` between fields. This will be our first design system component, and we'll also include styles for the `label` contained in this class.

Create the `form-group` Component Styles

Learn how to begin addressing browser inconsistencies by resetting base styles across text inputs, textareas, and selects. We'll also review a few quirks related to mobile browsers and responsive design when dealing with form fields. And we'll uncover how to normalize `<select>` which was formerly one of the trickiest fields but is vastly easier now thanks to modern CSS through the `appearance` property.

Create Reset Styles to Normalize Form Fields Cross-Browser

We'll begin to apply our theme styles for our text inputs by creating the `.form-field` component. We'll make use of the Sass feature of "mixins" to create `:focus` and `:disabled` styles that can be reused. While creating the `:focus` and `:disabled` states we'll discuss the importance of contrast and keyboard access for accessibility.

An important take-away is that you need at least a 3:1 contrast ratio between your border and background AS WELL AS a 3:1 contrast ratio between your border and focus state.

Use Sass Mixins to Style Inputs with Accessible Contrast and Keyboard Access

Using modern CSS and in particular CSS grid and `clip-path` we can define cross-browser compatible custom select CSS styles inclusive of the dropdown arrow. We'll continue ensuring all styles are re-themeable by using the Sass functions we've already created within our form design system. We will style both the default single select, and a multi-select using `multiple`.

Create Custom Form Select and Multi-select CSS Styles

In the previous lesson, we set up the initial state styles for form selects and multi-selects. Now we'll add styles for the focus and disabled states, inclusive of a workaround necessary due to the lack of a parent selector in CSS.

The way we will get around this for our focus styles is to add a sibling span element to apply the styles and position those styles on top of the Select element.

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