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Elm best practices

Style guide

Elm 0.17.1

Install

This is a patch release. Everything is the same, just slightly better!

The main changes are:

Default dependencies in elm-package.json are elm-lang/core and elm-lang/html.
Error messages for elm-package are improved (e.g. this and this)

Docker - How to cleanup (unused) resources

Once in a while, you may need to cleanup resources (containers, volumes, images, networks) ...

delete volumes

// see: https://github.com/chadoe/docker-cleanup-volumes

$ docker volume rm $(docker volume ls -qf dangling=true)

$ docker volume ls -qf dangling=true | xargs -r docker volume rm

Should be work with 0.18

Destructuring(or pattern matching) is a way used to extract data from a data structure(tuple, list, record) that mirros the construction. Compare to other languages, Elm support much less destructuring but let's see what it got !

Tuple

myTuple = ("A", "B", "C")
myNestedTuple = ("A", "B", "C", ("X", "Y", "Z"))

npm shrinkwrap is useful, but maddening (once it's in place and you want to update a package).

Say you've got a package.json with module ember-cli as a devDependency currently at version 1.13.1. And you have an npm-shrinkwrap.json file too, generated with the --dev flag.

If you change the version of ember-cli to, say, 1.13.8 in package.json and run npm install, nothing will happen.

If you do that and manually change references in the shrinkwrap file, you will still have trouble (as nested dependencies may now be incorrect).

So what do we actually do?

Hello, visitors! If you want an updated version of this styleguide in repo form with tons of real-life examples… check out Trellisheets! https://github.com/trello/trellisheets

Trello CSS Guide

“I perfectly understand our CSS. I never have any issues with cascading rules. I never have to use !important or inline styles. Even though somebody else wrote this bit of CSS, I know exactly how it works and how to extend it. Fixes are easy! I have a hard time breaking our CSS. I know exactly where to put new CSS. We use all of our CSS and it’s pretty small overall. When I delete a template, I know the exact corresponding CSS file and I can delete it all at once. Nothing gets left behind.”

You often hear updog saying stuff like this. Who’s updog? Not much, who is up with you?

	defmodule Map.Helpers do
	@moduledoc """
	Functions to transform maps
	"""

	@doc """
	Convert map string camelCase keys to underscore_keys
	"""
	def underscore_keys(nil), do: nil

	port module Spelling exposing (..)

	import Html exposing (..)
	import Html.App as App
	import Html.Attributes exposing (..)
	import Html.Events exposing (..)
	import String


	main =

	;; A nock interpreter
	(defun tar (a f)
	(labels ((fas (b a)
	(declare (integer b))
	(cond
	((= b 1) a)
	((= b 2) (car a))
	((= b 3) (cdr a))
	((evenp b) (car (fas (/ b 2) a)))
	((oddp b) (cdr (fas (/ (1- (the integer b)) 2) a))))))

	;;; packages.el --- elm Layer packages File for Spacemacs
	;;
	;; Copyright (c) 2012-2014 Sylvain Benner
	;; Copyright (c) 2014-2015 Sylvain Benner & Contributors
	;;
	;; Author: Sylvain Benner <sylvain.benner@gmail.com>
	;; URL: https://github.com/syl20bnr/spacemacs
	;;
	;; This file is not part of GNU Emacs.
	;;