Man Vuong kidlab

This is a proposal for a lightning talk at Reactive Conf. Please 🌟 this gist to push the proposal!

Combining snapshot testing and component library

Do you test presentational logic of your components? No? Yes, but you feel like you are writing a lot of dummy tests? You even probably use snapshot tests for that, but don't feel like you make enought value from them..

If so, click 🌟 button on that Gist!

I'll talk how our team is using snapshot testing to iterate faster,

Cheat Sheet: Simple Authentication in Rails 6 with `has_secure_password`

The goal of this cheatsheet is to make it easy to add hand-rolled authentication to any rails app in a series of layers.

First the simplest/core layers, then optional layers depending on which features/functionality you want.

`Specs`
AUTHOR	Ira Herman
LANGUAGE/STACK	Ruby on Rails Version 4, 5, or 6

First, add pry-rails to your Gemfile:
https://github.com/rweng/pry-rails

gem 'pry-rails', group: :development

Then you'll want to rebuild your Docker container to install the gems

Use curl to get the JSON response for the latest release
Use grep to find the line containing file URL
Use cut and tr to extract the URL
Use wget to download it

curl -s https://api.github.com/repos/jgm/pandoc/releases/latest \
| grep "browser_download_url.*deb" \
| cut -d : -f 2,3 \
| tr -d \" \

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

Clarify and agree on the scope of the system

User cases (description of sequences of events that, taken together, lead to a system doing something useful)
- Who is going to use it?
- How are they going to use it?

Finding a Ruby memory leak using a time analysis

When developing a program in Ruby, you may sometimes encounter a memory leak. For a while now, Ruby has a facility to gather information about what objects are laying around: ObjectSpace.

There are several approaches one can take to debug a leak. This discusses a time-based approach, where a full memory dump is generated every, say, 5 minutes, during a time that the memory leak is showing up. Afterwards, one can look at all the objects, and find out which ones are staying around, causing the

	begin
	require "bundler/inline"
	rescue LoadError => e
	$stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
	raise e
	end

	gemfile(true) do
	source "https://rubygems.org"

	CREATE TABLE large_test (num1 bigint, num2 double precision, num3 double precision);

	INSERT INTO large_test (num1, num2, num3)
	SELECT round(random()10), random(), random()142
	FROM generate_series(1, 20000000) s(i);

	EXPLAIN (analyse, buffers)
	SELECT num1, avg(num3) as num3_avg, sum(num2) as num2_sum
	FROM large_test
	GROUP BY num1;

	module FactoryGirl
	module Doctor
	module FloatDuration
	refine Float do
	def duration
	t = self
	format("%02d:%02d.%03d", t / 60, t % 60, t.modulo(1) * 1000)
	end
	end
	end

	'use strict'

	const timeout = ms => new Promise(res => setTimeout(res, ms))

	function convinceMe (convince) {
	let unixTime = Math.round(+new Date() / 1000)
	console.log(`Delay ${convince} at ${unixTime}`)
	}

	async function delay () {