\documentclass[10pt,a4paper]{article}

% Packages
\usepackage{fancyhdr}           % For header and footer
\usepackage{multicol}           % Allows multicols in tables
\usepackage{tabularx}           % Intelligent column widths
\usepackage{tabulary}           % Used in header and footer
\usepackage{hhline}             % Border under tables
\usepackage{graphicx}           % For images
\usepackage{xcolor}             % For hex colours
%\usepackage[utf8x]{inputenc}    % For unicode character support
\usepackage[T1]{fontenc}        % Without this we get weird character replacements
\usepackage{colortbl}           % For coloured tables
\usepackage{setspace}           % For line height
\usepackage{lastpage}           % Needed for total page number
\usepackage{seqsplit}           % Splits long words.
%\usepackage{opensans}          % Can't make this work so far. Shame. Would be lovely.
\usepackage[normalem]{ulem}     % For underlining links
% Most of the following are not required for the majority
% of cheat sheets but are needed for some symbol support.
\usepackage{amsmath}            % Symbols
\usepackage{MnSymbol}           % Symbols
\usepackage{wasysym}            % Symbols
%\usepackage[english,german,french,spanish,italian]{babel}              % Languages

% Document Info
\author{raffi001}
\pdfinfo{
  /Title (nodejs.pdf)
  /Creator (Cheatography)
  /Author (raffi001)
  /Subject (Nodejs Cheat Sheet)
}

% Lengths and widths
\addtolength{\textwidth}{6cm}
\addtolength{\textheight}{-1cm}
\addtolength{\hoffset}{-3cm}
\addtolength{\voffset}{-2cm}
\setlength{\tabcolsep}{0.2cm} % Space between columns
\setlength{\headsep}{-12pt} % Reduce space between header and content
\setlength{\headheight}{85pt} % If less, LaTeX automatically increases it
\renewcommand{\footrulewidth}{0pt} % Remove footer line
\renewcommand{\headrulewidth}{0pt} % Remove header line
\renewcommand{\seqinsert}{\ifmmode\allowbreak\else\-\fi} % Hyphens in seqsplit
% This two commands together give roughly
% the right line height in the tables
\renewcommand{\arraystretch}{1.3}
\onehalfspacing

% Commands
\newcommand{\SetRowColor}[1]{\noalign{\gdef\RowColorName{#1}}\rowcolor{\RowColorName}} % Shortcut for row colour
\newcommand{\mymulticolumn}[3]{\multicolumn{#1}{>{\columncolor{\RowColorName}}#2}{#3}} % For coloured multi-cols
\newcolumntype{x}[1]{>{\raggedright}p{#1}} % New column types for ragged-right paragraph columns
\newcommand{\tn}{\tabularnewline} % Required as custom column type in use

% Font and Colours
\definecolor{HeadBackground}{HTML}{333333}
\definecolor{FootBackground}{HTML}{666666}
\definecolor{TextColor}{HTML}{333333}
\definecolor{DarkBackground}{HTML}{C2C2C2}
\definecolor{LightBackground}{HTML}{F7F7F7}
\renewcommand{\familydefault}{\sfdefault}
\color{TextColor}

% Header and Footer
\pagestyle{fancy}
\fancyhead{} % Set header to blank
\fancyfoot{} % Set footer to blank
\fancyhead[L]{
\noindent
\begin{multicols}{3}
\begin{tabulary}{5.8cm}{C}
    \SetRowColor{DarkBackground}
    \vspace{-7pt}
    {\parbox{\dimexpr\textwidth-2\fboxsep\relax}{\noindent
        \hspace*{-6pt}\includegraphics[width=5.8cm]{/web/www.cheatography.com/public/images/cheatography_logo.pdf}}
    }
\end{tabulary}
\columnbreak
\begin{tabulary}{11cm}{L}
    \vspace{-2pt}\large{\bf{\textcolor{DarkBackground}{\textrm{Nodejs Cheat Sheet}}}} \\
    \normalsize{by \textcolor{DarkBackground}{raffi001} via \textcolor{DarkBackground}{\uline{cheatography.com/41042/cs/12495/}}}
\end{tabulary}
\end{multicols}}

\fancyfoot[L]{ \footnotesize
\noindent
\begin{multicols}{3}
\begin{tabulary}{5.8cm}{LL}
  \SetRowColor{FootBackground}
  \mymulticolumn{2}{p{5.377cm}}{\bf\textcolor{white}{Cheatographer}}  \\
  \vspace{-2pt}raffi001 \\
  \uline{cheatography.com/raffi001} \\
  \end{tabulary}
\vfill
\columnbreak
\begin{tabulary}{5.8cm}{L}
  \SetRowColor{FootBackground}
  \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Cheat Sheet}}  \\
   \vspace{-2pt}Published 14th August, 2017.\\
   Updated 14th August, 2017.\\
   Page {\thepage} of \pageref{LastPage}.
\end{tabulary}
\vfill
\columnbreak
\begin{tabulary}{5.8cm}{L}
  \SetRowColor{FootBackground}
  \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Sponsor}}  \\
  \SetRowColor{white}
  \vspace{-5pt}
  %\includegraphics[width=48px,height=48px]{dave.jpeg}
  Measure your website readability!\\
  www.readability-score.com
\end{tabulary}
\end{multicols}}




\begin{document}
\raggedright
\raggedcolumns

% Set font size to small. Switch to any value
% from this page to resize cheat sheet text:
% www.emerson.emory.edu/services/latex/latex_169.html
\footnotesize % Small font.

\begin{multicols*}{3}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Server Example}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{const http = require('http'); \newline  \newline const hostname = '127.0.0.1'; \newline const port = 3000; \newline  \newline const server = http.createServer((req, res) =\textgreater{} \{ \newline   res.statusCode = 200; \newline   \seqsplit{res.setHeader('Content-Type'}, 'text/plain'); \newline   res.end('Hello World\textbackslash{}n'); \newline \}); \newline  \newline server.listen(port, hostname, () =\textgreater{} \{ \newline   console.log(`Server running at http://\$\{hostname\}:\$\{port\}/`); \newline \});} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Cluster}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{const cluster = require('cluster'); \newline const http = require('http'); \newline const numCPUs = \seqsplit{require('os').cpus().length;} \newline  \newline if (cluster.isMaster) \{ \newline   console.log(`Master \$\{process.pid\} is running`); \newline  \newline   // Fork workers. \newline   for (let i = 0; i \textless{} numCPUs; i++) \{ \newline     cluster.fork(); \newline   \} \newline  \newline   cluster.on('exit', (worker, code, signal) =\textgreater{} \{ \newline     console.log(`worker \$\{worker.process.pid\} died`); \newline   \}); \newline \} else \{ \newline   // Workers can share any TCP connection \newline   // In this case it is an HTTP server \newline   http.createServer((req, res) =\textgreater{} \{ \newline     res.writeHead(200); \newline     res.end('hello world\textbackslash{}n'); \newline   \}).listen(8000); \newline  \newline   console.log(`Worker \$\{process.pid\} started`); \newline \}} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{A single instance of Node.js runs in a single thread. To take advantage of multi-core systems the user will sometimes want to launch a cluster of Node.js processes to handle the load. \newline  \newline The cluster module allows you to easily create child processes that all share server ports.}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{DNS}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{const dns = require('dns'); \newline  \newline dns.lookup('nodejs.org', (err, addresses, family) =\textgreater{} \{ \newline   console.log('addresses:', addresses); \newline \}); \newline  \newline  \newline const dns = require('dns'); \newline  \newline dns.resolve4('archive.org', (err, addresses) =\textgreater{} \{ \newline   if (err) throw err; \newline  \newline   console.log(`addresses: \$\{JSON.stringify(addresses)\}`); \newline  \newline   addresses.forEach((a) =\textgreater{} \{ \newline     dns.reverse(a, (err, hostnames) =\textgreater{} \{ \newline       if (err) \{ \newline         throw err; \newline       \} \newline       console.log(`reverse for \$\{a\}: \$\{JSON.stringify(hostnames)\}`); \newline     \}); \newline   \}); \newline \});} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.53827 cm} x{2.43873 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Globals}}  \tn
% Row 0
\SetRowColor{LightBackground}
\_\_dirname & \_\_filename \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
\seqsplit{clearImmediate(immediateObject)} & \seqsplit{clearInterval(intervalObject)} \tn 
% Row Count 3 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\seqsplit{clearTimeout(timeoutObject)} & console \tn 
% Row Count 5 (+ 2)
% Row 3
\SetRowColor{white}
exports & global \tn 
% Row Count 6 (+ 1)
% Row 4
\SetRowColor{LightBackground}
module & process \tn 
% Row Count 7 (+ 1)
% Row 5
\SetRowColor{white}
require() & require.cache \tn 
% Row Count 8 (+ 1)
% Row 6
\SetRowColor{LightBackground}
require.resolve() & setImmediate(callback{[}, ...args{]}) \tn 
% Row Count 10 (+ 2)
% Row 7
\SetRowColor{white}
\seqsplit{setInterval(callback}, delay{[}, ...args{]}) & \seqsplit{setTimeout(callback}, delay{[}, ...args{]}) \tn 
% Row Count 12 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Query String}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{const querystring = require('querystring'); \newline  \newline querystring.parse('w=\%D6\%D0\%CE\%C4\&foo=bar', null, null, \newline   \{ decodeURIComponent: gbkDecodeURIComponent \}); \newline  \newline querystring.stringify(\{ foo: 'bar', baz: {[}'qux', 'quux'{]}, corge: '' \});} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Assert}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{const assert = require('assert'); \newline  \newline const obj1 = \{ \newline   a: \{ \newline     b: 1 \newline   \} \newline \}; \newline const obj2 = \{ \newline   a: \{ \newline     b: 2 \newline   \} \newline \}; \newline const obj3 = \{ \newline   a: \{ \newline     b: 1 \newline   \} \newline \}; \newline const obj4 = Object.create(obj1); \newline  \newline assert.deepEqual(obj1, obj1); \newline // OK, object is equal to itself \newline  \newline assert.deepEqual(obj1, obj2); \newline // AssertionError: \{ a: \{ b: 1 \} \} deepEqual \{ a: \{ b: 2 \} \} \newline // values of b are different \newline  \newline assert.deepEqual(obj1, obj3); \newline // OK, objects are equal \newline  \newline assert.deepEqual(obj1, obj4); \newline // AssertionError: \{ a: \{ b: 1 \} \} deepEqual \{\} \newline // Prototypes are ignored} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Console}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{const out = getStreamSomehow(); \newline const err = getStreamSomehow(); \newline const myConsole = new console.Console(out, err); \newline  \newline myConsole.log('hello world'); \newline // Prints: hello world, to out \newline myConsole.log('hello \%s', 'world'); \newline // Prints: hello world, to out \newline myConsole.error(new Error('Whoops, something bad happened')); \newline // Prints: {[}Error: Whoops, something bad happened{]}, to err \newline  \newline const name = 'Will Robinson'; \newline myConsole.warn(`Danger \$\{name\}! Danger!`); \newline // Prints: Danger Will Robinson! Danger!, to err} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{eRROR}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{try \{ \newline   const m = 1; \newline   const n = m + z; \newline \} catch (err) \{ \newline   // Handle the error here. \newline \} \newline  \newline  \newline  \newline  \newline const fs = require('fs'); \newline   fs.readFile('a file that does not exist', (err, data) =\textgreater{} \{ \newline     if (err) \{ \newline       console.error('There was an error reading the file!', err); \newline       return; \newline     \} \newline     // Otherwise handle the data \newline   \}); \newline  \newline  \newline const net = require('net'); \newline const connection = \seqsplit{net.connect('localhost');} \newline  \newline // Adding an 'error' event handler to a stream: \newline connection.on('error', (err) =\textgreater{} \{ \newline   // If the connection is reset by the server, or if it can't \newline   // connect at all, or on any sort of error encountered by \newline   // the connection, the error will be sent here. \newline   console.error(err); \newline \}); \newline  \newline connection.pipe(process.stdout);} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{http}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{const http = require('http'); \newline const keepAliveAgent = new http.Agent(\{ keepAlive: true \}); \newline options.agent = keepAliveAgent; \newline http.request(options, onResponseCallback); \newline  \newline  \newline http.get(\{ \newline   hostname: 'localhost', \newline   port: 80, \newline   path: '/', \newline   agent: false  // create a new agent just for this one request \newline \}, (res) =\textgreater{} \{ \newline   // Do stuff with response \newline \});} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Readline}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{const readline = require('readline'); \newline  \newline const rl = readline.createInterface(\{ \newline   input: process.stdin, \newline   output: process.stdout \newline \}); \newline  \newline rl.question('What do you think of Node.js? ', (answer) =\textgreater{} \{ \newline   // TODO: Log the answer in a database \newline   console.log(`Thank you for your valuable feedback: \$\{answer\}`); \newline  \newline   rl.close(); \newline \});} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Buffer}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{// Creates a zero-filled Buffer of length 10. \newline const buf1 = Buffer.alloc(10); \newline  \newline // Creates a Buffer of length 10, filled with 0x1. \newline const buf2 = Buffer.alloc(10, 1); \newline  \newline // Creates an uninitialized buffer of length 10. \newline // This is faster than calling Buffer.alloc() but the returned \newline // Buffer instance might contain old data that needs to be \newline // overwritten using either fill() or write(). \newline const buf3 = Buffer.allocUnsafe(10); \newline  \newline // Creates a Buffer containing {[}0x1, 0x2, 0x3{]}. \newline const buf4 = Buffer.from({[}1, 2, 3{]}); \newline  \newline // Creates a Buffer containing UTF-8 bytes {[}0x74, 0xc3, 0xa9, 0x73, 0x74{]}. \newline const buf5 = Buffer.from('tést'); \newline  \newline // Creates a Buffer containing Latin-1 bytes {[}0x74, 0xe9, 0x73, 0x74{]}. \newline const buf6 = Buffer.from('tést', 'latin1');} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Events}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{const myEmitter = new MyEmitter(); \newline myEmitter.on('event', function(a, b) \{ \newline   console.log(a, b, this); \newline   // Prints: \newline   //   a b MyEmitter \{ \newline   //     domain: null, \newline   //     \_events: \{ event: {[}Function{]} \}, \newline   //     \_eventsCount: 1, \newline   //     \_maxListeners: undefined \} \newline \}); \newline myEmitter.emit('event', 'a', 'b');} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{File System}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{fs.open('myfile', 'wx', (err, fd) =\textgreater{} \{ \newline   if (err) \{ \newline     if (err.code === 'EEXIST') \{ \newline       console.error('myfile already exists'); \newline       return; \newline     \} \newline  \newline     throw err; \newline   \} \newline  \newline   writeMyData(fd); \newline \}); \newline  \newline  \newline fs.watch('./tmp', \{encoding: 'buffer'\}, (eventType, filename) =\textgreater{} \{ \newline   if (filename) \newline     console.log(filename); \newline     // Prints: \textless{}Buffer ...\textgreater{} \newline \});} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{https}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{// curl -k https://localhost:8000/ \newline const https = require('https'); \newline const fs = require('fs'); \newline  \newline const options = \{ \newline   key: \seqsplit{fs.readFileSync('test/fixtures/keys/agent2-key.pem')}, \newline   cert: \seqsplit{fs.readFileSync('test/fixtures/keys/agent2-cert.pem')} \newline \}; \newline  \newline https.createServer(options, (req, res) =\textgreater{} \{ \newline   res.writeHead(200); \newline   res.end('hello world\textbackslash{}n'); \newline \}).listen(8000);} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Stream}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{const http = require('http'); \newline  \newline const server = http.createServer((req, res) =\textgreater{} \{ \newline   // req is an http.IncomingMessage, which is a Readable Stream \newline   // res is an http.ServerResponse, which is a Writable Stream \newline  \newline   let body = ''; \newline   // Get the data as utf8 strings. \newline   // If an encoding is not set, Buffer objects will be received. \newline   req.setEncoding('utf8'); \newline  \newline   // Readable streams emit 'data' events once a listener is added \newline   req.on('data', (chunk) =\textgreater{} \{ \newline     body += chunk; \newline   \}); \newline  \newline   // the end event indicates that the entire body has been received \newline   req.on('end', () =\textgreater{} \{ \newline     try \{ \newline       const data = JSON.parse(body); \newline       // write back something interesting to the user: \newline       res.write(typeof data); \newline       res.end(); \newline     \} catch (er) \{ \newline       // uh oh! bad json! \newline       res.statusCode = 400; \newline       return res.end(`error: \$\{er.message\}`); \newline     \} \newline   \}); \newline \}); \newline  \newline server.listen(1337);} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Child Process}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{const spawn = \seqsplit{require('child\_process')}.spawn; \newline const ls = spawn('ls', {[}'-lh', '/usr'{]}); \newline  \newline ls.stdout.on('data', (data) =\textgreater{} \{ \newline   console.log(`stdout: \$\{data\}`); \newline \}); \newline  \newline ls.stderr.on('data', (data) =\textgreater{} \{ \newline   console.log(`stderr: \$\{data\}`); \newline \}); \newline  \newline ls.on('close', (code) =\textgreater{} \{ \newline   console.log(`child process exited with code \$\{code\}`); \newline \});} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{The child\_process.spawn() method spawns the child process asynchronously, without blocking the Node.js event loop. The \seqsplit{child\_process.spawnSync()} function provides equivalent functionality in a synchronous manner that blocks the event loop until the spawned process either exits or is terminated.}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}


% That's all folks
\end{multicols*}

\end{document}