JS Concepts

This is a small repository that I'm using to trial various javascript concepts. The primary goal is to follow a more functional approach to where appropriate.

Tests will live under tests in the related directory

Monads (/monads)

A pass at understanding and implementing something with monads.

Store (/store)

The first is my pass at a redux style store. It initially started as a functional observer pattern but then ended up being a redux-style store with observers

Event Store (/events)

I wanted to write a simple event store with 2 features around projection. Either wait until all projections have completed successfully before returning or fire them in the next tick immediately returning to the caller.

I feel waiting for projections to complete saves multiple client requests/polling. An API user will typically make a request and want to see the result or the action. Waiting for projections will allow this.

Test App (/app)

This is a simple express app that ties the event store and the redux style store together. It uses the events store to save Tasks to a database and has a store that the projections will write to. The state of the store is returned to the user after projections have been made.

To start:

run bin/setup-env.sh
run yarn start:app
Open your favourite API tool (curl/postman/insomnia?)
post to localhost:8001/tasks an event of the shape { task: 'my sweet task' }
Read the response

UI of the Test App (/app/tasks-ui)

A simple create-react-app client that will let you create/delete tasks using the event sourced app above.

To start in dev mode:

Run the /app above
In a new tab go to /app/tasks-ui
run yarn dev
Follow the prompts on screen and profit!

Function Event Emitter (/functional_events)

In an effort to greater develop my understanding of events and functional programming I've created an emitter that does not store any local state. The goal is to use a recursive approach to maintain state.

Functional App (/functional_app)

Using the functional emitter, and the state monad from the helpers (on further learning this is not actually a state monad. Further readings required), this is a simple application that prompts and adds items to a list. Events are emitted when an item is added and on quit.

aabrook/js_concepts