reborg

Rich Already Answered That!

A list of commonly asked questions, design decisions, reasons why Clojure is the way it is as they were answered directly by Rich (even when from many years ago, those answers are pretty much valid today!). Feel free to point friends and colleagues here next time they ask (again). Answers are pasted verbatim (I've made small adjustments for readibility, but never changed a sentence) from mailing lists, articles, chats.

How to use:

• The link in the table of content jumps at the copy of the answer on this page.
• The link on the answer itself points back at the original post.

Table of Content

jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

rgreenjr

-- show running queries (pre 9.2)
SELECT procpid, age(clock_timestamp(), query_start), usename, current_query 
FROM pg_stat_activity 
WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%' 
ORDER BY query_start desc;

-- show running queries (9.2)
SELECT pid, age(clock_timestamp(), query_start), usename, query 
FROM pg_stat_activity 
WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%' 

paulirish

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.

Element APIs

Getting box metrics

• elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent

jamtur01

These are the Kickstarter Engineering and Data role definitions for both teams.

Technical	Data	People
Junior Software Engineer
Software Engineer	Data Analyst
Senior Software Engineer	Data Scientist	Engineering Manager
Staff Engineer	VP of Data	Engineering Director
Principal Engineer		CTO

bobbygrace

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?

merlinmann

Merlin's Wisdom Project

Or: “Everybody likes being given a glass of water.”

By Merlin Mann.

It's only advice for you because it had to be advice for me.

rkumar

#!/usr/bin/env ruby -w
## Using ruby's standard OptionParser to get subcommand's in command line arguments
## Note you cannot do: opt.rb help command
## other options are commander, main, GLI, trollop...

# run it as
# ruby opt.rb --help
# ruby opt.rb foo --help
# ruby opt.rb foo -q
# etc

billybong

#!/usr/bin/env jjs
/*####################################################################################################################################
# As Nashorn does not have http capabilities through XMLHttpRequest (DOM API), we have to use regular Java classes instead.
# This sample shows how this can be acheived without depending on any third party libraries. Just a standard Java 8 JDK.
# Make sure to have JAVA_HOME/bin on your PATH for the shebang to work. Then just chmod +x away and run...
# Alternatively if you're on a non *nix OS, start with jjs -scritping httpsample.js
####################################################################################################################################*/

var url = "https://api.github.com/users/billybong/repos";
var response;

addyosmani

const puppeteer = require('puppeteer');

const Good3G = {
  'offline': false,
  'downloadThroughput': 1.5 * 1024 * 1024 / 8,
  'uploadThroughput': 750 * 1024 / 8,
  'latency': 40
};

const phone = puppeteer.KnownDevices['Nexus 5X'];