 Resources from Murphy Randle in 2022

Node.js is a well established server runtime that many companies are using worldwide. Express.js is a server framework for Node.js used by over 5 million projects. ReasonML is a type-safe functional language that compiles to Javascript.

This playlist collects the basic pieces of information a programmer needs to get started building servers in ReasonML on Node.js and Express.js. Follow along to learn how to get the speed of Node, combined with the added type-safety of Reason.

Node.js is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.

node

Making an HTTP server in ReasonML on top of Node.js

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.

Elm includes a data type called `Maybe` which is useful for working with values that may, or may not exist. This lesson shows a simple case where maybe types are encountered, and how to make them useful.

Using "Maybe" in Elm for values that may or may not exist

The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypermedia information systems. It is a generic, stateless, protocol which can be used for many tasks beyond its use for hypertext, such as name servers and distributed object management systems, through extension of its request methods, error codes and headers.

http

Understand the three basic parts of making HTTP requests in Elm: 1) Building the request, 2) Writing a JSON decoder, 3) Sending the request using the Elm runtime, and reacting to the results with messages.

HTTP requests are just pieces of data in Elm. When we want to send them, we hand them off to Elm's runtime, and it notifies us when the request is done. An important part of working with HTTP requests that fetch JSON is JSON decoding, the process by which we can turn untyped JSON data into Elm types that are safe to work with.

Specs:

- Editor: Atom
- Theme: [Nebula (with Nebula syntax theme)](https://atom.io/themes/nebula-ui)
- Font: [Iosevka with ligatures enabled](https://github.com/be5invis/Iosevka)
- Plugin used for imports: [Elmjutsu](https://atom.io/packages/elmjutsu)
- Plugin used for formatting: [Elm-format](https://atom.io/packages/elm-format)
- Plugin used for linting: [linter-elm-make](https://atom.io/packages/linter-elm-make)


Make an HTTP Request in Elm

Decoding JSON strings in Elm is a 2-step process:

1. Create a "recipe" for the decoding
2. Perform the decoding

This lesson gives a couple basic examples of the two steps in action.

Decode a List of Numbers From a JSON String in Elm

**Notice**:  This lesson uses Elm 0.17!

[Here's a document about the important differences between 0.16 and 0.17](https://github.com/elm-lang/elm-platform/blob/master/upgrade-docs/0.17.md).

This lesson gives a rapid-paced introduction to what's known as the Elm Application Architecture. You can read about it in greater detail here:

[guide.elm-lang.org](http://guide.elm-lang.org/architecture/index.html).

We'll build a counter that utilizes the standard Elm combination of a model, a view, and update function.

See the linked code for a good starting place.

Build a Tiny App Using the Standard Elm Architecture

This lesson will take you from nothing to a small Elm app that prints text to the browser.

Create your first web page with Elm

Turning JSON strings into types, also known as JSON Decoding is an important part of using Elm. It allows the programmer to use json-encoded data while staying completely aware of when the JSON might not match the programmer's expectations, all without throwing a run-time error! This lesson will show the viewer how to turn a simple JSON object into an analogous Elm record and use it to render some content to the screen.

Turn a JSON string Into Typed Data in Elm

Simple, fast & type safe code that leverages the JavaScript & OCaml ecosystems.

reason

ReasonML is a fantastic way to write Javascript! But it doesn't yet have a built-in async / await syntax. Furthermore the built-in libraries for working with Javascript promises are awkward to work with, and produce code that's hard to read. This lesson will teach the viewer how to use the "bs-let" language extension (called a PPX) to achieve readable, easy to write promise-based code.

Async / Await in ReasonML

Although ReasonML has built-in libraries for working with JSON, they are low-level and difficult to use by hand. The Decco library offers automatically generated JSON decoders, and produce a result that keeps the programmer safe at runtime by telling them whether the data they got matched the shape of the data they expected. 

Automatically decode JSON into records in ReasonML using Decco

Decco is a great library for automatically generating JSON encoders and decoders, but most real-world projects will quickly run into the need to add custom data types that Decco doesn't ship with support for. This lesson shows how to simply add a custom data type by implementing a codec that reads and writes Javascript dates as floats.

Write a simple custom JSON decoder for Decco in ReasonML

Decco is a language extension that automatically generates JSON encoders and decoders from type signatures. When adding adding custom Decoders, the error messages that the compiler produces can be quite confusing. This lesson shows the viewer how to use explicit type signatures to narrow down where an error might be coming from in custom codec code. This same pattern can be applied whenever confusing error messages come from code that is written without explicit type signatures.

Working with cryptic error messages from ReasonML when writing custom Decco decoders.

This lesson shows how the Serbet server library for ReasonML and Node.js makes handling JSON request bodies, and responding with JSON request bodies a simple task.

Handle JSON request bodies and send JSON responses from a Node.js server using ReasonML

This lesson shows how to use the `serbet` npm package to write a simple Node.js http server in ReasonML by implementing a simple "hello world" endpoint. Serbet is a convenient wrapper around Express.js. It's a young library, but its patterns are already used in production code.

Make a basic server with ReasonML and Node.js

Tailwind is a utility-first CSS framework for rapidly building custom user interfaces.

tailwind

This lessons shows how to dynamically add a red border to an input when a validation error pops occurs using ReasonReact, Tailwind, and re-classnames.

Murphy Randle