 Courses from Flavio Corpa

`elm-ui` is a language for layout and interface design. This is a novel iteration on declarative styling where you can use Elm types and functions to define your UI in a declarative way.

The novel part is that it does not require you to know CSS to be used. The API is very simple and can be learned quickly!

The approach taken by `elm-ui` is based on two big ideas: 
Getting the compiler to verify as much of the layout and styling as possible by defining them in Elm code
Enabling refactoring capabilities of Elm for UI code


Elm is a programming language that provides a clean functional syntax for writing HTML web applications. It promises zero runtime exceptions, fast rendering, time-travel debugging, and much more.

Declarative UIs without CSS with elm-ui

Now that our beautiful dashboard is complete, is time to produce a production ready build with create-elm-app, one of the biggest benefits of using it. You'll notice that it is running on production mode because the Elm Debugger won't show up anymore.

Create a Production Optimised Build with create-elm-app

We will make all the necessary changes to keep track within our model of the device and orientation that the user is using, and change our UI according with that information, adding responsiveness and multiple columns (at last!) to our dashboard.

To do this, we'll need to modify our app state to track the device height and width (which we expose from JavaScript). Then we can use the `classifyDevice` function to pattern match the devices we want to handle, in our case, `Desktop` and everything else (as mobile). We will add a `Browser.Events` subscription that sends a ResizedApp message to our model that defines what device we are on.

Manually Control Responsiveness with Elm classifyDevice

Up until this point, the 4 cards displayed in our dashboard each repeat the same information, so in this lesson, we will be splitting the state into different parts, showing an algebraic mindset and thinking how best represent the state of our app with our custom types. 

We'll start by modeling the selected options in state as a List of a Menu and String. The next step is to actually update the internal state of our menus. We will update `OptionPicked` to receive a string and when it does receive an option, it will filter for just the selected option and append that to state. Finally we will display the options in the `viewCard` component that will filter for the menu that is being selected and in the case of an option selected display that option as a string.

Split the Business Logic of Elm view Functions By Modeling the State

Since every time we interact with one of the dropdowns the information is shared between the 4 of them, the time as now arrives to give each individual dropdown its own state. We will also add subscriptions to listen to when the user clicks outside each dropdown!

To do this, we'll need to extend our state model to include each instance of our `viewCard`. To determine which dropdown that was clicked we will create a `getDropdownState` function that pattern matches the correct card instance. During this process, you'll see how the Elm compiler guides us through adding this functionality with detailed error messages.

You'll see how adding a subscription to close open dropdowns is convenient as `Dropdown` gives us an `onOutsideClick` function that receives the model and dropdown message.

Give Multiple Dropdowns Their Own Individual State with elm-ui-dropdown

This is the only lesson in which we will fallback to CSS to give our dropdown's scrollbar a fancier look because this is very browser dependent and there is no way (yet) to do this with elm-ui.

Customize My First Checkbox Icon with elm-ui

Cascading Style Sheets bring order and beauty to our applications.

This is the **only** lesson in which we will fallback to CSS to give our dropdown's scrollbar a fancier look because this is very browser dependent and there is no way *(yet)* to do this with elm-ui.

We will target `::-webkit-scrollbar`, `::-webkit-scrollbar-track`, and `::-webkit-scrollerbar-thumb` to get the scrollbar looking exactly how we want it.

Customize the Dropdown Scrollbar with CSS

Now that our dropdown is almost finished lets just drop some shadow in the options selector to make it more visually clear that its over any other element in our page. This is an attribute that we can control the `offset`, `size`, `blur`, and `color`.

We will want to do this to our `viewCard` as well. We will also make the `viewCard` function more flexible by adding additional `Html` attributes from the outside to make each card have a different **height.** That way any time you want to override default attributes, you can pass in a new style.

Add elm-ui Border.shadow to Highlight Any Element

Since there is no select or dropdown component backed in into elm-ui, we will be adding another dependency to our project called `PaackEng/elm-ui-dropdown` and adding to it additional styles and settings so that it looks and behaves exactly as we want to.

To make this works, we need to make a few changes:
- We need to add a `dropdownState : Dropdown.State String` to our `Model`
- Add a couple of extra variants to our `Msg` type: `OptionPicked (Maybe String)`, to be dispatched by our dropdown whenever we click on any option, and `DropdownMsg (Dropdown.Msg String)` to update the internal state of the dropdown from the outside.
- Construct our hardcoded list of options of type `List String`.
- Define a `dropdownConfig : Dropdown.Config String Msg` that is going to contain all our customisation of our dropdown.
- Use `Dropdown.view` to display our custom dropdown wherever we need it.

Customize My Own Dropdown with elm-ui-dropdown

Now that we have our cards more or less looking good lets add a button and style it as well so that it serves as a starting point for our dropdown component, this lesson will also help us to learn how to use the `Element.Input` module from elm-ui.

Work with elm-ui Input Components

In this lesson, we will explain when you would need to reach for the `text` function, why it is different from `textColumn` and `paragraph` and when to use each one as they serve different purposes for displaying text in the UI. Basically, `el` and `text` elements **do not wrap text by default**, so we need to use `paragraph` when we want text to overflow and still be visible to read. We will add a new "subtitle" section below our Breakdown subheading

Choose between text, textColumn and paragraph with elm-ui

Since we mentioned in a previous lesson that there is no concept of "margin" in elm-ui, we are goint to learn how to se `padding`, `paddingXY` and `paddingEach` to compensate for that, and a little trick defining a value edges that is going to be pretty useful.

Use padding, paddingXY and paddingEach with elm-ui

We will style the heading of `viewCards` to look more like a real heading. If you inspect the console right now, you'll find that the `el` element we are using for our text corresponds to a div in HTML. 

We will go further away than using only text to display our content and introduce the modules `Element.Font` and `Element.Region` to fix the headlines and other text of our dashboard, adding an additional "breakdown" heading that is going to serve as a divider between sections.

Style Text with elm-ui Headlines, Typographies, and Fonts

We will use the pink box element that we had from previous lessons while implementing our fancy dashboard and we will turn it into our Card "component", the piece of UI that we are going to repeat and that will have its own state later on the course. 

To do this, we'll first manipulate the background color and text color, then change the height and width of the card. We will want to change the title for each of the cards and to do so we will accept a title argument that will be passed down to our text element within the card to be displayed.

Use View Functions to Create Reusable Pieces of UI in Elm

In this lesson we will start to get to know the row and column functions in elm-ui to help us layout our application. We will choose the mobile first approach in which we will display everything in one column, show how to handle two columns and explain that later when we do responsible we will be able to play a bit more with this. Since the concept of margin does not exist in elm-ui, in this lesson we learn how to solve it by using spacing and we will talk about padding in a future lesson.

Model a Layout with row, column and spacing with elm-ui

To showcase the power of elm-ui, in this lesson we will show how incredibly easy it is to center an element both horizontally and vertically on a screen with elm-ui, since this is a typical problem while doing regular CSS.

Center an elm-ui Element Horizontally and Vertically

We are going to go ahead and install globally create-elm-app (because it has the best DX so far) and show how would you typically start any production-ready Elm app, and also add elm-ui as a dependency and show the first elements with elm-ui.

Bootstrap an elm-ui Application with create-elm-app

Welcome to the elm-ui course! We are going to be building a complex dashboard completely from scratch with elm-ui, with a mobile-first approach and in the final lessons of the course we will make it fully responsive! I hope you enjoy the course and that you choose elm-ui for your next project!

Introduction to the elm-ui Course

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

We are so tied to libraries that we use things like underscore or JQuery whenever we want to do any simple operation, we'll see how to get rid of this practice by knowing a little better JavaScript's native array methods and, along the way, remove those unneeded dependencies!

Use Native JavaScript Array Methods instead of Dependency Library

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

Starting from v15.5 if we wanted to use React's PropTypes we had to change our code to use a separate node module, now we can go one step further and get rid of that extra dependency just by using flow type annotations in our create-react-app project!

Remove React PropTypes by using Flow Annotations (in CRA)



Discover how to harness the power of Cursor IDE's Composer Agent feature to optimize your code. In this lesson, you'll witness an AI agent doing all the work to generate test suites, implement performance benchmarks, and create optimized function variations - all without writing a single line of code. You'll learn how to validate performance improvements through data-driven benchmarking, ensuring that optimizations are backed by concrete metrics rather than speculation. This hands-on demonstration showcases a groundbreaking approach to automated function development that combines the precision of test-driven development with the efficiency of AI-powered optimization.


Agent-Driven Development in Cursor: Testing, Benchmarking, and Optimizing Functions

This course is aimed for using `zod` effectively in projects based on TypeScript (both browser and node.js). The benefits you gain with this course is not just simply coding, but also understanding when/why/how should you perform runtime validation.

`zod` is the missing piece to TypeScript's capabilities, which can guarantee type-safety only in compile-time.

`zod` can be used whenever the compiler cannot guarantee what happens in runtime. And... it's a very frequent usecase, such as HTTP calls, websockets, etc.

In this course you get quickly up and running by:
1. using `zod` with primitives and objects
2. adapting `zod` quickly to existing projects thanks to automatic generators
3. changing the strategy frm type-first to schema-first
4. using error-throwing `parse` or non-error-throwing `safeParse` basing on your needs
5. applying `zod` to the most common usecase - validating API responses
6. handling errors the most convenient way (out of many!)

Take advantage of runtime validation with `zod`. Take advantage of the detailed lessons in this course 🔥

Effective Runtime Type Checks with Zod


Cursor can now automatically run commands in the terminal and walk step-by-step towards building out your entire project. You give it a goal, then it will suggest the commands you need to run and the files that you need to create and you can work with it to achieve what you're building. This lesson does a quick walkthough of using a Cursor Agent to build a project from scratch and guide it along the way. Cursor Agents definitely feel like a sneak peek at the future of programming!

Cursor Agents Initial Impressions - Allow an AI to Build Your Entire Project

Mock Service Worker is an API mocking library that allows you to write client-agnostic mocks and reuse them across any frameworks, tools, and environments.



Mocking WebSocket APIs with Mock Service Worker


While using anonymous functions might seem convenient, they can create difficulties when trying to identify performance bottlenecks during profiling. This lesson will demonstrate how named functions make it easier to pinpoint and address performance issues, ultimately leading to more efficient and debuggable code. Learning this practice will greatly improve your ability to locate and fix performance issues in complex projects.

Always Name Functions in JavaScript


When attempting to load the same module twice in JavaScript you'll hit a cache and code won't re-run. In scenarios where you actually do want to have state in your modules, you'll have to use a cache-busting technique by passing a query parameter to a dynamic import. This lesson walks through how to add a query parameter, how to add the appropriate types for loading dynamic modules in TypeScript, and when these techniques are valuable.

Import the Same JavaScript Module Multiple Times with Cache Busting



The include keyword in GitHub Actions empowers you to add custom variables to your matrix strategy, providing flexibility beyond standard configurations. In this video, we'll explore how include allows you to define specific combinations of variables, enhancing control over your workflow runs. You'll see how this feature enables you to tailor jobs for unique environments or scenarios not covered by the default matrix options. By leveraging include, you can efficiently manage complex build processes with greater precision. This technique helps you streamline your CI/CD pipeline, making it more adaptable to your project's evolving needs.

Use GitHub Actions Matrix Include for Complex Job Configurations

While running `zod` schema validation agains domain-rich objects, the error message saying that _a string is not a number_ might not be really useful.

Especially, when you need to provide a meaningful feeback to the user, e.g. after they have submitted a form with lots of data.

`zod` allows to customize messages on a very granular level. We can also extract repeatable customization to `zod` error maps.

Finally, in order to process an error message further (e.g. display it to the user), we need to handle the `zod` validation errors effectively. Especially, when a big object validation has failed and we could receive a handful of errors.

That's what we learn in this lesson. 🔥

Customize zod Error Messages and Handle zod Errors Effectively

customize zod validation messages, customize zod schema property messages, reuse error maps across different schemas, navigate through zod error objects

You might want to run `zod` schema checks in different styles.

Sometimes you prefer to conditionally throw the error - that's what `parse` does. But another time you'd prefer to receive a `boolean` property that determines whether the validation was successful or not - and perform further actions accordingly.

Additionally, the error-throwing API of `parse` works extremely well with [TypeScript assertion functions](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-7.html#assertion-functions). Their combination is just... perfect! 👌

That's what we learn in this lesson.

Use parse and safeParse Runtime Type-checks with zod

use zod parse function to conditionally throw ZodError, use zod safeParse to get a boolean value and run typescript type guard over success property

In this lesson we learn that TypeScript cannot guarantee correct shapes of responses. That's due to TS performing checks in compile-time, while the response will be availbale in runtime - when TS doesn't exist anymore.

In some situations, such as HTTP requests, runtime type checks such as `zod` are essential for providing quick feedback around data-related errors.

Understand where are the possible mistakes to make while using TypeScript with HTTP calls. Use `fetch` and `axios` along with `zod` schema checks.

Also, note that similar mistakes or mistakes could happen while using web storage (e.g. `localStorage`)

Validate HTTP API Response with zod, fetch and axios

use zod as an HTTP response validation tool along with fetch and axios in order to make sure that the response has expected data structure

Flavio Corpa

Declarative UIs without CSS with elm-ui

Search Results

Declarative UIs without CSS with elm-ui

Create a Production Optimised Build with create-elm-app

Manually Control Responsiveness with Elm classifyDevice

Split the Business Logic of Elm view Functions By Modeling the State

Give Multiple Dropdowns Their Own Individual State with elm-ui-dropdown

Customize My First Checkbox Icon with elm-ui

Customize the Dropdown Scrollbar with CSS

Add elm-ui Border.shadow to Highlight Any Element

Customize My Own Dropdown with elm-ui-dropdown

Work with elm-ui Input Components

Choose between text, textColumn and paragraph with elm-ui

Use padding, paddingXY and paddingEach with elm-ui

Style Text with elm-ui Headlines, Typographies, and Fonts

Use View Functions to Create Reusable Pieces of UI in Elm

Model a Layout with row, column and spacing with elm-ui

Center an elm-ui Element Horizontally and Vertically

Bootstrap an elm-ui Application with create-elm-app

Introduction to the elm-ui Course

Use Native JavaScript Array Methods instead of Dependency Library

Remove React PropTypes by using Flow Annotations (in CRA)