Learn Ember, Polymer and Svelte

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

Ember is a javascript framework that provides a rich set of tools for building modern web applications. Unlike many frameworks, Ember comes with opinions and a way of doing things so you aren't left with a ton of decisions to make about problems that have already been solved very well. Ember was designed from the start to deliver a productive and comfortable experience for you, the developer.

In this course you will learn what you need to know to get started building your own Ember we applications. From the absolute essentials like creating a new project with the Ember-CLI tools, templating, routing, and reusable components.



A JavaScript framework for creating ambitious web applications.

ember

Ember 2 Fundamentals

Polymer is a framework created at Google for building reusable web components.

We use HTML elements every day such as div, a, button, form, and table. All HTML elements provide some sort of API of attributes, properties, methods and events that we use to manipulate them. Generally, web elements are styled in a particular way by default, and also allow us to customize their styling with CSS.

Polymer allows you to build fully custom web elements of your own for more complex components composed of the building blocks you are used to with the standard set of HTML elements.

This course is an introduction to Polymer, and should get you started building your own customizable web elements that you can use on their own, or even with your favorite framework like Angular or React!

The Polymer library provides a set of features for creating custom elements. These features are designed to make it easier and faster to make custom elements that work like standard DOM elements.

polymer

Creating Custom Web Elements with Polymer 2

Creating forms is one of the simplest and most complicated things at the same time. A basic form consists of many different things happening, we have to retain the value, we have to keep watch of validation and we have to show error messages when something is invalid, this is on both the fields and on the entire form itself if we send a request off to the backend service.

So we're going to create a form using just the normal svelte features. Then we'll look into creating a form using the svelte forms lib. 

Create forms in Svelte with Svelte Forms Lib

Components in Ember are great for reusing code throughout our application. We’ll see how each instance of an Ember component has isolated state and we can over ride as well as set default values.

In this lesson, we will learn how to make a simple, reusable component within an Ember application.

Create Simple Components in Ember

In this lesson, we learn how to create nested routes and templates in an Ember.js application, in addition to how to create nested routes and isolated templates.

Creating nested routes in Ember.js

In this lesson, we will learn how templates work within Ember and how to use HTMLBars. This lesson will cover the connection between controllers and templates and how to use actions within templates as well.

Ember Templating with HTMLBars

In this lesson, we will learn how to install Ember Inspector and use it to see the state of our application and debug it.

The Ember Inspector can be installed from the [Chrome Web Store](https://chrome.google.com/webstore/detail/ember-inspector/bmdblncegkenkacieihfhpjfppoconhi). We will see how the inspector gives us access to information such as the routes available to us, the components used in a particular view, and data that is exposed to us etc.


Debug Ember Applications using Ember Inspector

In this lesson we'll look at creating event listeners in our custom element using the listeners object as well as annotated event listeners.

Create Event Listeners in Polymer Elements

In Ember.js, functions that are executed through user interaction with your application are called actions, which can be defined at the route, controller, or component level. In this tutorial, we look at a simple example of defining actions on the controller and hooking it up to our template in order to update properties on the controller.

Add user interaction to Ember.js apps using actions

We will learn how to install Ember-CLI and use it to create a new Ember project. We will also learn how to run the Ember project.

Create an Ember Project with the Ember-CLI

In this lesson, we show how to specify a model for an Ember Route so its data can be displayed. 

Define Models for Routes in 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

In this lesson, we will learn how to define routes within an Ember application and how to use them to navigate around your application. This lesson will cover the basics of routes and how we can use nested routes to display multiple templates at the same time. We can also cover redirect routes and manually forcing transitions through actions.

Define Routes in Ember 2.0 using Ember-CLI

Custom element property changes can be observed by specifying an observer method which will be executed whenever a change occurs and receive both the new value and old value.

Observe Property Changes on a Custom Polymer Element

In this lesson we'll look at the lifecycle callbacks (Created, Ready, Attached, Detached, and attributeChanged) available to us in Polymer and how to use each one.

Use Lifecycle Callbacks On Custom Polymer Elements

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

Polymer provides us a variety of data-binding configurations.  In this lesson we'll look at configuring Two-way, One-way-down and One-way-up data binding.

Data Bind Two Polymer Elements

Closure actions are useful for extending application code such as modifying a property on a controller while also sending up information from a component.
In this lesson, we learn how to use closure actions with Ember.js components. 

Use Closure Actions with Ember Components

We can utilize the "fire" method from within our custom element to execute a custom event.  In this lesson we'll create a custom event and pass useful data along with the event to the consumer of our element.