metainfa

Architecture in Elm

This document is a collection of concepts and strategies to make large Elm projects modular and extensible.

We will start by thinking about the structure of signals in our program. Broadly speaking, your application state should live in one big foldp. You will probably merge a bunch of input signals into a single stream of updates. This sounds a bit crazy at first, but it is in the same ballpark as Om or Facebook's Flux. There are a couple major benefits to having a centralized home for your application state:

There is a single source of truth. Traditional approaches force you to write a decent amount of custom and error prone code to synchronize state between many different stateful components. (The state of this widget needs to be synced with the application state, which needs to be synced with some other widget, etc.) By placing all of your state in one location, you eliminate an entire class of bugs in which two components get into inconsistent states. We also think yo

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

-E: will describe the underlaying queries of the \ commands (cool for learning!)
-l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

THIS GIST WAS MOVED TO TERMSTANDARD/COLORS REPOSITORY.

PLEASE ASK YOUR QUESTIONS OR ADD ANY SUGGESTIONS AS A REPOSITORY ISSUES OR PULL REQUESTS INSTEAD!

	// Include module references.
	var stream = require( "stream" );
	var util = require( "util" );
	var chalk = require( "chalk" );


	// ---------------------------------------------------------- //
	// ---------------------------------------------------------- //

	// Include module references.
	var events = require( "events" );
	var stream = require( "stream" );
	var util = require( "util" );
	var chalk = require( "chalk" );


	// ---------------------------------------------------------- //
	// ---------------------------------------------------------- //

	// initialize the Shanghai component which keeps track of
	// shipping data in and out of the Port of Shanghai.
	var shanghai = Elm.worker(Elm.Shanghai, {
	coordinates:[0,0],
	incomingShip: { name:"", capacity:0 },
	outgoingShip: ""
	});

	function logger(x) { console.log(x) }

	<html>

	<head>
	<title>Embedding Elm in HTML!</title>
	<script type="text/javascript" src="elm.js"></script>
	</head>

	<body>
	<h1>Stamper</h1>
	<div id="stamper" style="width:50%; height:400px;"></div>

	require('font-awesome/css/font-awesome.css');

	document.body.innerHTML = '<i class="fa fa-fw fa-question"></i>';

	someStream.on( "error", function( error ) {

	this.emit( "end" );

	});