hellerbarde

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

MichalZalecki

/* VT100 terminal reset (<ESC>c) */

console.log('\033c');

/* numbers comparations */

> '2' == 2
true

> '2' === 2

kharandziuk

This article shows how to apply Node.js Stream and a bit of Reactive programming to a real(tm) problem. The article is intended to be highly practical and oriented for an intermediate reader. I intentionally omit some basic explanations. If you miss something try to check the API documentation or its retelling(e.g.: this one)

So, lets start from the problem description. We need to implement a simple web scraper which grabs all the data from some REST API, process the data somehow and inserts into our Database. For simplicity, I omit the details about the actual database and REST API(in real life it was the API of some travel fare aggregator website and a Pg database)

Consider we have two functions(code of the IO simulator functions and the other article code is here):

getAPI(n, count) // pseudo API ca

marcan

/* SMBLoris attack proof-of-concept
 * 
 * Copyright 2017 Hector Martin "marcan" <marcan@marcan.st>
 *
 * Licensed under the terms of the 2-clause BSD license.
 *
 * This is a proof of concept of a publicly disclosed vulnerability.
 * Please do not go around randomly DoSing people with it.
 *
 * Tips: do not use your local IP as source, or if you do, use iptables to block

hugoferreira

/*
 * 'Origami Programming' by Hugo Sereno Ferreira
 *
 * IEEE Talk @ FEUP (2018)
 *
 * Exercise sheet (http://goo.gl/Dd4p7b)
 *
 * Note: Make sure you have node.js, and then install the dependencies using:
 *
 * npm install -g lodash

ricardojba

::##########################################################################################################################
::
:: This script can ruin your day, if you run it without fully understanding what it does, you don't know what you are doing,
::
::                             OR BOTH!!!
:: 
::                     YOU HAVE BEEN WARNED!!!!!!!!!!
:: 
:: This script is provided "AS IS" with no warranties, and confers no rights.
:: Feel free to challenge me, disagree with me, or tell me I'm completely nuts in the comments section, 

atanasyanew

# Telegraf Configuration
#
# Telegraf is entirely plugin driven. All metrics are gathered from the
# declared inputs, and sent to the declared outputs.
#
# Plugins must be declared in here to be active.
# To deactivate a plugin, comment out the name and any variables.
#
# Use 'telegraf -config telegraf.conf -test' to see what metrics a config
# file would generate.