Learn Ember, Rails and Svelte

Web3 is a paradigm shift in how applications are interacted with, ran, and built. 

It’s not just a Pump-and-Dump scheme on cryptocurrencies or Bored Ape NFT profile pictures you can put on Twitter.

A fundamental tenet of Web3 is bringing ownership back to the user. You no longer have to trust that your data is being properly handled on someone else’s server (although, currently Web3 ecosystem mainly depends on centralized infrastructure such as GitHub).  

This ownership is achieved through blockchain, cryptocurrencies, NFTs, and smart contracts.

A great example of this type of ownership is through how you exchange money in Web3. There is no intermediary like Stripe, or PayPal to process your transactions. You can even build your own smart contracts that receive crypto (e.g. Ethereum or ‘eth’ for short) and then process that eth how you’d like.

Building this type of smart contract is exactly what Matías is going to show you how to do right now.

Matías builds out a Web3 application that allows you to receive tips in the form of eth in a tip jar on your website. This means your application will be backed by a smart contract that’s accepts eth, stores data, and emits Solidity events.

The frontend application uses SvelteKit which you’ll see how easy it is to get up and be productive with in minutes. A huge benefit here is that the JavaScript you write is just that, JavaScript. You’ll be able to take what you learn and implement it into any framework of your choosing.

While you build this application you will learn how to:

- Write a smart contract using Solidity language
- Test the smart contract using just JavaScript through the waffle framework
- Communicate and interact with the smart contract using ethers.js in a SvelteKit application
- Deploy your smart contract to make it public and accessible to anyone

Solidity is an object-oriented, high-level language for implementing smart contracts.

solidity

Full Stack Web3 and Blockchain Development on Ethereum with SvelteKit

JavaScript community has been shaken recently by a release of Svelte 3 and for a good reason - it's a completely different approach than React or Vue. To quote the docs:

"[Svelte](https://svelte.dev/) is a radical new approach to building user interfaces. Whereas traditional frameworks like React and Vue do the bulk of their work in the browser, Svelte shifts that work into a compile step that happens when you build your app."

**The best part?** If you have 26 spare minutes you can learn the basics of Svelte 3 and start building your own apps with it!

Enjoy!



The magical disappearing UI framework

 - The web's JavaScript bloat crisis, solved. Svelte turns your templates into tiny, framework-less vanilla JavaScript.
 - Simple and familiar. Build apps out of composable, easy-to-write blocks using languages you already know.
 - Super fast, rock solid. Compile-time static analysis ensures the browser does no more work than it needs to.

svelte

Up and running with Svelte 3

Rails is a web-application framework that includes everything needed to create database-backed web applications according to the Model-View-Controller (MVC) pattern.

rails

Expanding on [Part 1](https://egghead.io/lessons/angularjs-rails-todo-api-part-1), this lesson will look at how to bootstrap AngularJS in a rails application as part of the asset pipeline. With Angular available, you'll see how to communicate with the Rails API using $resource.

Rails Todo API Part 2

A JavaScript framework for creating ambitious web applications.

ember

In this lesson we will create an `updateContent` method that sets the value of our `content` property to the current epoch timestamp. We need to call `toString()` on the `Date.now()` method in order to make TypeScript happy.

```
updateContent() {
  this.content = Date.now().toString()
}
```

We create a constructor that takes the options parameter, call `super(options)` and call into our `this.updateContent()` method.

```
constructor(options) {
  super(options)
  this.updateContent()
}
```

When we refresh our page we can see that the value of `content` is set to the epoch timestamp. 

To make the content really dynamic we use `setInterval()` to call into `updateContent` each second: `setInterval(() => this.updateContent(), 1000)`.

When we save our file we see that our content does not get updated anymore and when we check the console we see that we get an error telling us that: The 'content' property on the my-component component was changed after it had been rendered. The error also informs us that we should Use the @tracked decorator to mark this as a tracked property.

We add the @tracked decorator to our property, we import tracked from @glimmer/component and we refresh the page. We verify that `content` gets updated each second.

We change our `updateContent` to add our the timestamp to the array. When we use `this.items.push(this.content)` to achieve this we see that the list does not get updated. This is because the `@tracked` decorator only tracks the re-assignment of properties.

The way to get this working is by re-assigning our `items` array inside `updateContent`. We assign a new array, de-structure the current items array and add the new content.

```
this.items = [...this.items, this.content]
```



Use dynamic data in a GlimmerJS component

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

Rails makes an excellent choice for delivering data to AngularJS via REST apis. In this first lesson of a two part series, you'll see how to create a simple API for CRUD operations on TODOs using Rails. This isn't an introduction to Rails, and assumes you know the basics. 

Rails Todo API Part 1

In this lesson we will use the ember cli to generate a new component. Running `ember g glimmer-component my-component` generates the template and component class. We change the content of our component and add it to the main template in order to show it on the page.

Create a new GlimmerJS component

In this lesson we will add a variable called `content` to our component class, initialize it as a string and display the variable in our class using the double curly braces syntax, which is the handlebars expression for expressions, `{ {content }}`. 

After this we create a new class variable called `items`, initialize it as an array with strings. To display this list in our template we add a `<ul></ul>` and inside this unordered list we use the handlebars `each` helper to display the list items.

And inside our each statement we will print a `<li>` tag and render `{{ item}}` inside it.

```
<ul>
  {{#each items key="@index" as |item| }}
    <li>{{item}}</li> 
  {{/each}}
</ul>
```



Use template variables in a GlimmerJS component

[GlimmerJS](https://glimmerjs.com/) is a UI component library built by the Ember.js team. It is fast and lightweight and uses a combination of TypeScript and Handlebars to build the components.   

In this lesson we will use the Ember CLI to initialize a new GlimmerJS project.

We will start by installing Ember CLI globally by running `npm install -g ember-cli/ember-cli`.

Next we will use the `ember` command to create our new project by running `ember new egghead-glimmer -b @glimmer/blueprint` . 

When our project is created we `cd` into the project directory and start the development server. We will view the page in the browser and change the base template.

Initialize a project using Glimmer.js

Create a search directive with AngularJS and Rails. You'll want to take a look at the related [Rails TODO API Part 1](https://egghead.io/lessons/angularjs-rails-todo-api-part-1) and [Rails TODO API Part 2](https://egghead.io/lessons/angularjs-rails-todo-api-part-2). This is **not** a Rails how-to, so some knowledge there is expected to get up and running.

Search Directive with Rails

In this lesson you will learn how to attach Event Handlers to buttons and input fields. Event handlers normally follows the `on:[event]` format. If you are making use of two way binding you should use `bind:` instead, for example an input field could use bind:value.

Use Event Handlers in Svelte 2

Learn how to test ActiveRecord named scopes using RSpec.

In this lesson, we will test a `User` model that will have a `by_ci_email` method 
that we will define on the model. We will test this method in our `user_spec.rb` file and pass in a lower case email argument to demonstrate that the `by_ci_email` method is functioning correctly by finding the correct user.

Test ActiveRecord Named Scopes

Learn how to test ActiveRecord validations using RSpec.

In this lesson we'll write a test that expects the `name` attribute to be present on the User model instance. We'll see that at first this test fails because we need to add this validation on the model.

Test ActiveRecord Validations

Svelte is a new approach to building user interfaces. 

Instead of doing the vast majority of work at the runtime as other frameworks do, Svelte shifts that work into the _compile_ step which happens when you build your app. As such, you're shipping heavily optimized code to your users.

In this quick lesson we are going to learn how to create a brand new project with Svelte 3 from scratch.

Create a new project with Svelte 3

In most Web applications we want to be able to render different HTML markup depending on values passed in from JavaScript code.

In this lesson we are going to learn how to render JavaScript variable in HTML markup when using Svelte 3.

Add data to HTML markup using Svelte 3

In Svelte 3, the same as in regular HTML we can add CSS styles to a component and this is what we're going to learn in this lesson.

Important note - styles are _scoped to the component_ which means that if we style a `h1` tag in component A, it won't automatically affect `h1` tags in component B.

Add styles to Svelte 3 component

One of the key advantages of having a component system is the ability to render the component differently based on what kind of properties (shortened to 'props' in Svelte) were passed in to the component.

In this lesson we are going to learn how to declare properties inside of a Svelte component and how to pass in data to be rendered inside of a `<UserInfo />` component. We're also going to learn how to use default props which are used if a value for a property was not passed in.

Declare and pass in properties to a Svelte 3 component

Svelte automatically updates the DOM when your component's state changes. Often, some parts of a component's state need to be computed from other parts. This is where _reactive declarations_ come in.

In this lesson we are going to learn how to use reactive declarations to re-compute (and render) square of a counter value in a simple counter example whenever user clicks on a button.

Use reactive declarations to compute component state in Svelte 3

It's highly unlikely that we'd like to have an entire app in a single file. Instead, what we'd like to do is to spread our code across multiple components and render them in one another.

In this lesson we are going to learn how to create a `<Surname />` Svelte 3 component which we're going to use in our main `App.svelte` file to display a user's surname.

Create a new Svelte 3 component to render it inside of another component

Quite often we need to be able to loop over and render a list of data that (for example) is returned from the backend. 

In this lesson we are going to learn how to use `each` block from Svelte to iterate over a list of data and render a list of European cities. We're also going to learn how to get the current `index` while iterating over a list, as well as how to destructure a currently iterated over element of the array.

Loop over and render a list of data using an `each` block in Svelte 3

Learn how to test custom ActiveRecord validations using RSpec.

In this lesson we'll write a test that expects the `email` to be found on the `invitations` table. We'll see that at first this test fails because we need to add the custom validation on the user model. Once we implement the validation and create the `InvitedValidator`, the test will pass.

Test Custom ActiveRecord Validations

The whole magic of webapps is that users can interact with our code via various DOM events and Svelte is no exception in that regard.

In this quick lesson we're going to learn how to use DOM events in Svelte 3 as well as how to use event _modifiers_ to alter DOM event behaviour (such as `once` and `preventDefault`)

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