Learn Babel, Chai and Jekyll

Jekyll is a blog-aware static site generator. You can write text in markdown or HTML and Jekyll uses layouts to create a static website. You can tweak how you want the site URLs to look, what data gets displayed on the site, and more.

After watching the collection you'll be able to:

* Install Jeykll and run it locally
* Create a new blog post
* Install plugins to add new features to your blog

Jekyll is a parsing engine bundled as a ruby gem used to build static websites from dynamic components such as templates, partials, liquid code, markdown, etc. Jekyll is known as "a simple, blog aware, static site generator".

jekyll

Create A Blog With Jekyll

npm is the package manager for JavaScript. Find, share, and reuse packages of code from hundreds of thousands of developers — and assemble them in powerful new ways.

We can write our package using the latest JavaScript syntax with a compilation step. In this lesson we will install `babel-cli` and `babel-preset-latest` and wire up a `build` script to compile our code using the babel “latest” preset when source files change. This means those using our package can use it in any version of JavaScript even though we are using the latest syntax for our source code.

Set up compilation of source code using babel with npm scripts

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

chai

[Chai](https://npmjs.com/package/chai) assertions work great with the [Mocha](https://npmjs.com/package/mocha) testing framework. In this lesson we'll walk through out to install Chai and [karma-chai](https://npmjs.com/package/karma-chai) so you can use the `expect` assertions in your tests.

Use Chai assertions for tests in a Karma project

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

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

Babel has support for the latest version of JavaScript through syntax transformers. These plugins allow you to use new syntax, right now without waiting for browser support.

babel

What is already a nice workflow using Gulp, Browserify, Watchify & Browsersync to enable auto rebuilds & live browser reloading can be further improved by adding Babelify. A simple wrapper around the popular transpiler Babel, Babelify can ‘transform’ source files as they pass through our stream to enable certain Javascript features not yet available in the Browser or Node. We end the lesson by looking at how to generate & extract sourcemaps using `exorcist`.

Gulp and Browserify - Adding Babel & Source Maps

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

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.

Test for HTTP 400 responses with Mocha and Chai

Babel is a compiler that lets us right future JavaScript not yet fully in browsers (ES6 / ES2015, ES7 / ES2016, etc) and transpile it back into code that can be used now. We'll walk through installing babel, writing some future JS syntax, transpiling it, and running it in a browser.

**This lesson is out of date and uses an older version of Babel.**

Writing next generation JavaScript with Babel 5 (out of date)

webpack is a tool to build JavaScript modules in your application. To start using webpack from its cli or api, follow the Installation instructions. webpack simplifies your workflow by quickly constructing a dependency graph of your application and bundling them in the right order. webpack can be configured to customise optimisations to your code, to split vendor/css/js code for production, run a development server that hot-reloads your code without page refresh and many such cool features.

webpack

Webpack loaders are how you tell webpack to resolve your dependencies and you can use a loader built for the babel transpiler to easily enable ES6 code in your project. Full sourcemap support is also available using webpack's devtool property.

Webpack Loaders, Source Maps, and ES6

[Jekyll](https://jekyllrb.com/) is a static site generator built in [Ruby](https://www.ruby-lang.org/en/) and available to generate and host websites on [GitHub Pages](https://pages.github.com/). In this course, you'll install the Jekyll gem, use the command line tool to generate a new project, inspect the scaffolded project, and finally, serve the starter website.

Install Jekyll and generate initial, scaffolded website

In this lesson, we’ll install Babel and use it from the terminal to see how it can take JavaScript that uses modern language features and output JavaScript that will run in down-level browsers.

Transform Modern JavaScript Features with Babel

In this lesson, we'll configure webpack to use the Babel loader for our JavaScript files, allowing us to transpile our source files and generate a bundle for deploying our application.

Configure webpack to Load JavaScript Files through Babel with babel-loader

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

In this lesson, we'll add React and ReactDOM to our project and create an entry point for the React application. We'll also configure Babel with the React preset so Babel can transpile our JSX into JavaScript that will run in a browser.

Configure babel for React with preset-react

We transpile our JavaScript code so we can use modern language features, even if browser support isn't quite where we need it to be. This includes proposed features that aren't yet part of the official language specification. In this lesson, we'll see how we can support the proposed class property syntax for JavaScript with a Babel plugin.

Support Proposed JavaScript Features with Babel Plugins

Converting all of our modern JavaScript into ES5 compatible syntax is a great way to use modern features while targeting older browsers. What happens when the browsers natively support these language features? Then it no longer makes sense to transform that code or to include polyfills that will go unused. In this lesson, we’ll add the `@babel/polyfill` package and configure `babel-preset-env`

Target specific browsers with babel-preset-env and the babel pollyfill

One approach to building high performance applications with `webpack` is to take advantage of code-splitting to only load the needed JavaScript on initial load and asynchronously load additional JavaScript bundles when needed. In this lesson, we'll create add some code-splitting to our placeholder application and configure our project to support the dynamic `import()` syntax.

Asynchronously Load webpack Bundles through Code-splitting and React Suspense

We take the opengraph image we wrote in codesandbox and copy it into our serverless function. We use Rollup to compile the component into an IIFE (immediately invoked function expression) that can run in our headless browser environment and cover a wide set of rollup plugins that we need for compatibility. We end the lesson having successfully screenshot our opengraph react component from our Netlify Function

**Note**:  Due to Netlify changing their handling, the path in `fs.readFileSync` is affected. Update to:
```js
const script = fs.readFileSync(path.resolve(__dirname, "image.js"), "utf-8");
```

Compiling a React to an IIFE with Rollup to execute and render in a headless browser

Jekyll is a blog-aware, static site generator written in Ruby. 

Requirements:
* Ruby version 2.5.0 or above
* RubyGems

Install the Jekyll Ruby gem on macOS quickly with just a few terminal commands and have a blog-aware site running locally.

Install Jekyll and Create a New Project

Blogging is built into Jekyll. You write blog posts as markdown or HTML files and Jekyll turns them blog posts. They follow a specific naming convention to be picked up and used by Jekyll

All blog post files require front matter. Front matter is a snippet of YAML at the top of a file. Front matter is used to set your layouts and meta data.

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