Guilherme Oliveira guigaoliveira

API de Banking

O sistema deve oferecer a possibilidade de usuários realizarem transações financeiras como saque e transferencia entre contas.

Um usuário pode se cadastrar e ao completar o cadastro ele recebe R$ 1000,00.

Com isso ele pode transferir dinheiro para outras contas e pode sacar dinheiro. O saque do dinheiro simplesmente manda um email para o usuário informando sobre o saque e reduz o seu saldo (o envio de email não precisa acontecer de fato, pode ser apenas logado e colocado como "placeholder" para envio de email de fato).

Nenhuma conta pode ficar com saldo negativo.

This content moved here: https://exploringjs.com/impatient-js/ch_arrays.html#quickref-arrays

React Best practices

I have summarized and compiled a list of React.JS best practices from various sources across the internet.

From the React docs

https://reactjs.org/docs/components-and-props.html
- props must be readonly
https://reactjs.org/docs/state-and-lifecycle.html

ESM modules in node: npm edition

The proposal you’re about to read is not just a proposal. We have a working implementation of almost everything we discussed here. We encourage you to checkout and build our branch: our fork, with the relevant branch selected. Building and using the implementation will give you a better understanding of what using it as a developer is like.

Our implementation ended up differing from the proposal on some minor points. As our last action item before making a PR, we’re writing documentation on what we did. While I loathe pointing to tests in lieu of documentation, they will be helpful until we complete writing docs: the unit tests.

This repo also contains a bundled version of npm that has a new command, asset. You can read the documentation for and goals of that comma

Not all random values are created equal - for security-related code, you need a specific kind of random value.

A summary of this article, if you don't want to read the entire thing:

Don't use Math.random(). There are extremely few cases where Math.random() is the right answer. Don't use it, unless you've read this entire article, and determined that it's necessary for your case.
Don't use crypto.getRandomBytes directly. While it's a CSPRNG, it's easy to bias the result when 'transforming' it, such that the output becomes more predictable.
If you want to generate random tokens or API keys: Use uuid, specifically the uuid.v4() method. Avoid node-uuid - it's not the same package, and doesn't produce reliably secure random values.
If you want to generate random numbers in a range: Use random-number-csprng.

You should seriously consider reading the entire article, though - it's

WebSockets - An Introduction

WebSockets is a modern HTML5 standard which makes communication between client and server a lot more simpler than ever. We are all familiar with the technology of sockets. Sockets have been fundamental to network communication for a long time but usually the communication over the browser has been restricted. The general restrictions

The server used to have a permanent listener while the client (aka browser) was not designated any fixed listener for a more long term connection. Hence, every communication was restricted to the client demanding and the server responding.
This meant that unless the client requested for a particular resource, the server was unable to push such a resource to the client.
This was detrimental since the client is then forced to check with the server at regular intervals. This meant a lot of libraries focused on optimizing asynchronous calls and identifying the response of asynchronous calls. Notably t

	#!/bin/bash

	find . -name '.js' -exec gsed -i "s/const \(.\) = require(\(.\))\.\(.\);/import { \3 as \1 } from \2;/g" '{}' ';'
	prettier-eslint --write '*/.js'
	find . -name '.js' -exec gsed -i "s/const \(.\) = require(\(.*\));/import \1 from \2;/g" '{}' ';'


	<!--
	This demo shows two ways to detect changes to a DOM node `.textContent`, one
	using a `MutationObserver` and the other using an ES2015 `Proxy`.

	From testing, a `Proxy` appears to be 6-8x faster than using a MO in Chrome 50.

	Update: removing the `Proxy` altogether speeds up the MO to be inline with the Proxy.
	This has something to do with how the browser queues/prioritizes Proxies over MO.

	# Hello, and welcome to makefile basics.
	#
	# You will learn why `make` is so great, and why, despite its "weird" syntax,
	# it is actually a highly expressive, efficient, and powerful way to build
	# programs.
	#
	# Once you're done here, go to
	# http://www.gnu.org/software/make/manual/make.html
	# to learn SOOOO much more.