Learn Alpine, Mocha and Redwoodjs

Welcome to this beginner level series on Alpine JS! 👋🏞

Alpine JS is a rugged, minimal framework for composing JavaScript behaviour in your markup. It brings declarative, reactive, data-driven nature of libraries like React or Vue to your HTML templates.

In this series, you will learn about Alpine's handy **directives**. You'll discover how to define a component scope with `x-data`, run code on mount with `x-init`, attach event listeners with `x-on`, display data with `x-text`, decide wether or not to show an element with `x-show`, iterate through data with `x-for`, retrieve a DOM element with `x-ref`, learn how to achieve _two-way data binding_ with `x-model`, and much more.

You'll also learn how **"modifiers"** can be applied and chained to directives to provide additional functionality: control the animation transition of entering and leaving DOM elements, debounce an event listener, etc.

We'll also touch on what Alpine calls **"magic properties"**, which give you access to native browser events (`$event`), reference to DOM elements (`$refs`), and more.

You'll gradually discover Alpine's API and syntax, from building simple tabs to a mini app that fetches a dog picture based on a "breed" search field. 🐶

**Get ready to breathe some fresh air** - it's time to walk into cool, green Alpine pastures! 🏞

Alpine.js offers you the reactive and declarative nature of big frameworks like Vue or React at a much lower cost.

You get to keep your DOM, and sprinkle in behavior as you see fit.

alpine

Sprinkle declarative, reactive behaviour on your HTML with Alpine JS

RedwoodJS takes the JAMstack philosophy to the next level. It brings together all the tools modern web development has to offer:

- React
- GraphQL
- Prisma

RedwoodJS abstracts database management away from you so that you can just build your schema and it will do all the plumbing. This collection will go over how to create a RedwoodJS project and the scripts that will help make your developer experience a joy.


Bringing full-stack to the JAMstack

Do you love the JAMstack philosophy but need a database-backed web app? Want great developer experience and easy scaling? Redwood is here! Built on React, GraphQL, and Prisma, Redwood works with the components and development workflow you love, but with simple conventions and helpers to make your experience even better.

redwoodjs

Introduction to RedwoodJS: full-stack framework for JAMstack

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

We use `yarn redwood generate page` (`yarn rw` for short) in this lesson to generate an `IndexPage` component. 

The first argument to `yarn rw generate page` is the name of the page you are generating. The second argument is the path you want the page to show up on. So `yarn rw generate page index /` will generate an `IndexPage` component and insert a route entry in our `web/src/Routes.js` file.

We learn that redwood import `React` for you so you don't have to import it manually when you are creating a component.

Generate a Page Using the Redwood CLI

In this lesson, we are going over how to generate a `RedwoodJS` project.

We can create a `RedwoodJS` project with `yarn create redwood-app ./my-redwood-project`.

`yarn` will generate the `RedwoodJS` app in the file folder you specified without installing any globals.

To run the `RedwoodJS` app, we use `yarn redwood dev`. This runs the Redwood client as well as the `GraphQL` backend.

Generate a Redwood Project

RedwoodJS provides a `Link` component that we can use to navigate around our app. We can provide a `to` prop with the path that we want to navigate to.

RedwoodJS takes this a step further and provides a `routes` object from `@redwoodjs/router`. This object is aware of all the routes defined in `web/Routes.js`. This allows us to use the methods on this object rather than referencing the our routes with a string literal. We can then change the route path without having to change all of the references to that route all over our app.

Use RedwoodJS Link and routes Object to Navigate

RedwoodJS gives us a cli command to generate layouts.

`yarn redwood generate layout main`

This will generate a `MainLayout` component in `src/layouts/MainLayout/`. We can use this layout component to define any headers or footers we want to share across multiple pages. 

Extract a RedwoodJS Layout Component

In this lesson, we learn how the `x-init` directive in Alpine JS lets us run a JavaScript expression once the component has initiated.

We see the nuances that allow us to trigger that code before Alpine performs initial DOM updates, or after these updates have been made.

Focus in input field on page load with `x-init` in Alpine JS

In this lesson, we define a "count" state value with the `x-data` directive provided by Alpine JS. This defines a new scoped component, which can have access to this state.

We then display the "count" value in our HTML with the `x-text` directive, which updates an element's `innerText` value.

We also hook up buttons with click event listeners with `x-on:click`, which allows us to modify the count value as desired.

Update a count state value with the x-on event listener directive in Alpine JS

In this lesson, we create a set of tabs with Alpine JS, where only the content of the currently active tab is visible. To do this, we define an `activeTab` state value with `x-data. We then wire up our buttons to change the value of `activeTab` on click, and use `x-show` to determine if the tab content should be visible or not, based on the value of `activeTab`.

We also take control of the `class` attribute with `x-bind`, and we conditionally output an "active" class based on, you guessed it, the value of `activeTab`.

Toggle visibility and styles based on state with `x-show` and `x-bind` in Alpine JS

In this lesson, we move the component definition to a function, defined in a script tag in the HTML document.

We then iterate through an Array of Objects with the `x-for` directive in Alpine JS. We use a `<template>` tag to wrap the HTML element we want to repeat for each item, and put the `x-for` directive on that template tag.

We also define a "computed" property by adding a method on our function, which checks if a given ID matched the currently active tab id. This computed property allows us to determine wether or not to apply the "active" classname to our tab buttons.

Iterate through data with the `x-for` attribute in Alpine JS

In this lesson, we smoothen the transitions between tabs by applying a `transition` modifier to our `x-show` directive.

We see how we can ignore the leaving elements, and focus the animation on the entering elements. We tweak the transition duration and origin by chaining additional modifiers to our `x-show` directive.

Control enter and leave transitions with the `x-show.transition` modifier in Alpine JS

In this lesson, we see how the `x-model` directive makes achieving "two-way data binding" effortless in Alpine JS.

We see what it would take to recreate the same functionality with an `x-bind` directive for the input value, as well as an `@input` event listener which, thanks to an access to the browser's native events via the `$event` magic property, sets the state value to `$event.target.value`.

Keep a DOM input and state value in sync with the `x-model` directive in Alpine JS

In this lesson, we learn how to retrieve a DOM element via the `x-ref` directive in Alpine JS, which gives us a reference to the element it is applied on. In our case, an input field.

We can then use the `$refs` object, and reach for the ref we need to target.

This allows us to trigger the focus state of the input field, with the `.focus()` method.

Focus an input field on button click with `x-ref` and the `$refs` property in Alpine JS

In this lesson, we build a little app that fetches dog photos from the dog.ceo API, based on a "breed" search field. We want the API call to happen again when the search value changes, and to do so we use the `$watch` property from Alpine JS, which lets us define what state property we want to watch, and what callback function to run when a change happens.

We also use the `debounce` modifier on the `x-model` property to avoid firing an API call on each keystroke.

Refetch API data when a state value changes with the `$watch` property in Alpine JS

Welcome to this beginner level series on Alpine JS! 👋🏞

Alpine JS is a rugged, minimal framework for composing JavaScript behaviour in your markup. It brings declarative, reactive, data-driven nature of libraries like React or Vue to your HTML templates.

This is the series intro video. Let's get started!

Series Intro - Beginner Level Alpine JS

Mocha is a feature-rich JavaScript test framework running on Node.js and in the browser, making asynchronous testing simple and fun. Mocha tests run serially, allowing for flexible and accurate reporting, while mapping uncaught exceptions to the correct test cases.

mocha

Every dependable library needs to have tests to ensure that you don't push accidental bugs. In this lesson, see how you can set up mocha and chai to start testing your library.

Setting up Unit Testing with Mocha and Chai

Now that you've got everything set up with mocha and chai, it's time to actually write tests. In this lesson you'll learn how to use `describe` and `it` to outline your tests and make sure you don't break your library in the future.

Unit Testing with Mocha and Chai

Mocha is a testing framework that provides structure for unit tests. In this lesson, we will be setting up Mocha with npm and npm scripts, writing a "Hello World" unit test, then writing the code to make the test pass (as an example of Test Driven Development (TDD), with the "red-green-refactor" workflow).

JavaScript Testing Fundamentals: Hello world unit test with Mocha (in ES6)

In this lesson, we will use Chai's request method to test our Node application's API responses.
By the end of this lesson, you will know how to:
- install the prerequisites to use mocha and chai in your application
- test for HTTP status response codes
- test for a string of text on a page
- test for a json response and validate the properties of the object
- write tests that not only verify the response of your application, but the behavior as well


Test Node RESTful API with Mocha and Chai

Chai is a BDD / TDD assertion library for node and the browser that can be delightfully paired with any javascript testing framework.

chai

Writing great ES6 style Promises for Node.js is only half the battle. Your great modules must include tests as well to ensure future iterations don't break them. In this lesson, I show you a simple ES6 Promise in Node.js, then walk you through creating tests in Mocha using chai and chai-as-promised to test both resolve and reject methods.

Testing ES6 Promises in Node.js using Mocha and Chai

In this lesson, you will learn how to verify your API server is returning HTTP 400 responses when clients submit incorrect data. Returning HTTP 400 ensures that your clients are notified of the incorrect usage. Testing for them ensures your API returns errors instead of incorrect responses when supplied with incorrect data.

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