William Comnisky wcomnisky

JavaScript function hoisting by example

Below are many examples of function hoisting behavior in JavaScript. Ones marked as works successfuly print 'hi!' without errors.

To play around with these examples (recommended) clone them with git and execute them with e.g. node a.js

Notes on hoisting

(I may be using incorrect terms below, please forgive me)

This page provides a full overview of PHP's SessionHandler life-cycle - this was generated by a set of test-scripts, in order to provide an exact overview of when and what you can expect will be called in your custom SessionHandler implementation.

Each example is a separate script being run by a client with cookies enabled.

To the left, you can see the function being called in your script, and to the right, you can see the resulting calls being made to a custom session-handler registed using session_set_save_handler().

Inspired by dannyfritz/commit-message-emoji

Revert the full commit

Sometimes you may want to undo a whole commit with all changes. Instead of going through all the changes manually, you can simply tell git to revert a commit, which does not even have to be the last one. Reverting a commit means to create a new commit that undoes all changes that were made in the bad commit. Just like above, the bad commit remains there, but it no longer affects the the current master and any future commits on top of it.

git revert {commit_id}

About History Rewriting

Delete the last commit

Deleting the last commit is the easiest case. Let's say we have a remote origin with branch master that currently points to commit dd61ab32. We want to remove the top commit. Translated to git terminology, we want to force the master branch of the origin remote repository to the parent of dd61ab32:

	Terminal Commands:

	One webcam:

	ffmpeg -f alsa -ac 2 -i hw:1,0 -f v4l2 -s 1280x720 -r 10 -i /dev/video1 -vcodec libx264 -pix_fmt yuv420p -preset ultrafast -r 25 -g 20 -b:v 2500k -codec:a libmp3lame -ar 44100 -threads 6 -b:a 11025 -bufsize 512k -f flv rtmp://a.rtmp.youtube.com/live2/YOURSTREAMNAMEHERE

	Two webcam overlay:

	ffmpeg -f alsa -ac 2 -i hw:1,0 -f v4l2 -s 1280x720 -r 10 -i /dev/video1 -f v4l2 -s 320x240 -r 10 -i /dev/video0 -filter_complex "[1:v]setpts=PTS-STARTPTS[bg]; [2:v]setpts=PTS-STARTPTS[fg]; [bg][fg]overlay=shortest=1 [out]" -map "[out]" -map 0:a -vcodec libx264 -pix_fmt yuv420p -preset veryfast -r 25 -g 20 -b:v 2500k -codec:a libmp3lame -ar 44100 -threads 6 -b:a 11025 -bufsize 512k -f flv rtmp://a.rtmp.youtube.com/live2/YOURSTREAMNAMEHERE

	/*
	********************************************************************************
	Golang - Asterisk and Ampersand Cheatsheet
	********************************************************************************

	Also available at: https://play.golang.org/p/lNpnS9j1ma

	Allowed:
	--------
	p := Person{"Steve", 28} stores the value

	import java.io.File;
	import java.io.FileInputStream;
	import java.io.FileNotFoundException;
	import java.io.FileOutputStream;
	import java.io.IOException;
	import java.io.InputStream;
	import java.text.MessageFormat;

	import org.apache.commons.io.IOUtils;
	import org.jdom.input.DOMBuilder;

	#!/bin/bash
	if [[ $EUID -ne 0 ]]; then
	echo "This script must be run as root" 1>&2
	exit 1
	fi
	apt-get update
	apt-get install -y git-core autoconf bison libxml2-dev libbz2-dev libmcrypt-dev libcurl4-openssl-dev libltdl-dev libpng-dev libpspell-dev libreadline-dev make
	mkdir -p /etc/php7/conf.d
	mkdir -p /etc/php7/cli/conf.d
	mkdir /usr/local/php7

	<?php

	/**
	* Class BetterEnum
	*
	* A pure-PHP alternative to SplEnum, although only a 99% compatible replacement for it.
	*
	* See: http://php.net/manual/en/class.splenum.php
	*
	* To declare an enum class, subclass BetterEnum and define the names and values as constants.

Commit type	Emoji
Initial commit	🎉 `:tada:`
Version tag	🔖 `:bookmark:`
New feature	✨ `:sparkles:`
Bugfix	🐛 `:bug:`

	-- Get Max ID from table
	SELECT MAX(id) FROM table;

	-- Get Next ID from table
	SELECT nextval('table_id_seq');

	-- Set Next ID Value to MAX ID
	SELECT setval('table_id_seq', (SELECT MAX(id) FROM table));