Learn Babel, Elixir and Twit

These videos include the introductory steps to writing your first Elixir function and beginning to understand some key concepts in Elixir that make it unique. 

Some of those concepts include:
- the Mix build tool
- project structure
- collections of functions written in modules
- function *arity*
- pattern matching and common uses for it
- the pipe operator

Elixir is a dynamic, functional language designed for building scalable and maintainable applications.

Elixir leverages the Erlang VM, known for running low-latency, distributed and fault-tolerant systems, while also being successfully used in web development and the embedded software domain.

elixir

Getting Started with Elixir

In this course we’ll learn how to create Twitter bots. We’ll first learn how to interface with the Twitter API using Twit.js, which allows us to post statuses, search tweets, and interact with followers. We’ll create several example bots that show the diversity of possibilities, using powerful tools such as RiTa.js, Google’s Cloud Vision API, and Tracery. We’ll learn how to tweet data from Google Spreadsheets, and to compose and tweet a song for an audio bot. We’ll also learn how to host our bot logic on Heroku and Docker. 

Twitter API Client for node

Supports both the REST and Streaming API.

twit

Create your own twitter bots

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

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

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 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

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

Bootstrap a new Elixir project using Mix (a build tool included when you install Elixir), with its built in project generation.

Additional resources:
- [Official introduction to Mix](https://elixir-lang.org/getting-started/mix-otp/introduction-to-mix.html#our-first-project)

Generate a new Elixir project using Mix

Elixir code is organized into groups of functions called modules. You can create your own modules and built on top of predefined modules that are a part of Elixir by default.

Additional resources: 
- [Getting started with Modules and function from Elixir docs](https://elixir-lang.org/getting-started/modules-and-functions.html)

Write a New Function Inside of an Elixir Module

The syntax to pass arguments into functions is akin to many other languages. Elixir functions are uniquely recognized when running based off of the number of arguments passed in (a term called *arity*). This means you can define functions with the same name, so long as a different number of arguments is passed in.

Arity is a key concept to be aware of when reading documentation and writing your own code.

Additional resources:
- [Information about arity](https://elixir-lang.org/getting-started/modules-and-functions.html#function-capturing)
- [Default arguments in functions](https://elixir-lang.org/getting-started/modules-and-functions.html#default-arguments)

Pass arguments into Elixir functions and understand arity

Elixir uses `=` as an operator, but rather than assigning values to variables with it, it *matches* values on the right hand side of the `=` with the left side. This can be used in simple values, more complex data structures, and powerful condition checking.

Put into simpler terms, pattern matching is Elixir's way of assigning variables.

Additional resources:
- [Elixir docs on pattern matching](https://elixir-lang.org/getting-started/pattern-matching.html)

Pattern match values in Elixir

Some common uses for pattern matching in Elixir include checking conditions and passing parameters into functions. It's useful for pulling out only specific variables from collections of data.

Additional resources:
- [Elixir docs on pattern matching](https://elixir-lang.org/getting-started/pattern-matching.html)

Pattern match in conditions and function parameters in Elixir

We’ll get a real-time stream of tweets, and learn how to filter a stream by keyword, location, and user.

Use the Twitter Stream API with Twit.js

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

Gulp is a toolkit for automating painful or time-consuming tasks in your development workflow, so you can stop messing around and build something.

gulp

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

In this lesson, our bot will tweet hello to the Twitter world! We'll do this by using Twit's POST method to post our status to the statuses/update endpoint.

Post Statuses with Twit.js

In this lesson, we’ll create multiple functions to request, download, and save photos and data from NASA's API, and then have our bot upload these photos to Twitter and post them along with their descriptions. We'll also learn how to tweet videos using a video from NASA’s space archives.

Tweet Media Files with Twit.js

We’ll learn how your bot can get its list of followers, follow people, and look up friendships. We'll use Twit's GET method to get our followers at the followers/list endpoint, to get the users we follow at the friends/ids and friends/list endpoints, and to look up our friendships with the friendships/lookup endpoint. We'll also use Twit's POST method to follow someone at the friendships/create endpoint, and to send messages by posting to the direct_messages/new endpoint. 

Work with Users in Twit.js

We’ll learn the basics of interacting with tweets, including retweeting, deleting, favoriting, and replying to tweets. We'll get our home timeline by using Twit's GET method to access the `statuses/home_timeline` endpoint, including the count parameter, which lets us get back a certain number of tweets. We'll also pass it a callback. We'll learn how to cycle through the data (the tweets) we get back and see what information is included. We'll learn how to retweet statuses by posting to `statuses/retweet` and including the tweet id. We can unretweet by posting to `statuses/unretweet` with the same tweet id. We'll also learn how to like a tweet by posting to `favorites/create` with a tweet id, and unlike a tweet by posting to `favorites/destroy` with a tweet id. We'll also learn how to reply to a tweet by posting to `statuses/update`, with a status that includes the handle of the user we're replying to and `in_reply_to_status_id` parameter, which is the id of the tweet we're replying to. We'll learn how to delete a tweet by posting to `statuses/destroy` with the tweet's id. 

Interact with Tweets with Twit.js 

We’ll learn how to search tweets with the Twitter Search API, using Twit's GET method to get the search/tweets endpoint. We'll use the query and count parameters to get the search term(s) and number of tweets that we want. We'll learn how to get exact phrases, multiple words, one of several words, emoticons, hashtags, photos/videos, urls, and how to remove words from our results. We'll learn how to implement the safe filter and how to filter by media, website, or date. We'll learn how to get recent results, popular results, results by location, and results by language. 

The search API returns for relevance, and not completeness. If you want all the tweets from a search term, you should use the stream API (which we'll go over in the next lesson). 

Use the Twitter Search API with Twit.js

We’ll go over the basic Twitter bot setup, including how to start a project from scratch, install necessary packages, and store our private keys in environment variables. 

Set Up a Basic Twitter Bot with Twit.js

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 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

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.

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