\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{Techelopment (techelopment)}
\pdfinfo{
  /Title (javascript-basics.pdf)
  /Creator (Cheatography)
  /Author (Techelopment (techelopment))
  /Subject (JavaScript Basics Cheat Sheet)
}

% Lengths and widths
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\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}{A3A3A3}
\definecolor{LightBackground}{HTML}{F3F3F3}
\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{JavaScript Basics Cheat Sheet}}}} \\
    \normalsize{by \textcolor{DarkBackground}{Techelopment (techelopment)} via \textcolor{DarkBackground}{\uline{cheatography.com/212073/cs/46055/}}}
\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}Techelopment (techelopment) \\
  \uline{cheatography.com/techelopment} \\
  \end{tabulary}
\vfill
\columnbreak
\begin{tabulary}{5.8cm}{L}
  \SetRowColor{FootBackground}
  \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Cheat Sheet}}  \\
   \vspace{-2pt}Published 3rd April, 2025.\\
   Updated 3rd April, 2025.\\
   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*}{2}

\begin{tabularx}{8.4cm}{x{4.028 cm} x{2.584 cm} x{0.988 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{3}{x{8.4cm}}{\bf\textcolor{white}{Variables}}  \tn
% Row 0
\SetRowColor{LightBackground}
`\{\{lang-javascript\}\}let x = 10;` & block scope & most used \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
`\{\{lang-javascript\}\}const MAX = 100;` & constant values &  \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
`\{\{lang-javascript\}\}var y = 10;` & global or function scope & old usage \tn 
% Row Count 6 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}---}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{5.36 cm} x{2.64 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{Operators}}  \tn
% Row 0
\SetRowColor{LightBackground}
`\{\{lang-javascript\}\}let x = 10;` & assignment \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
`\{\{lang-javascript\}\}x == "Hello"` & comparison \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
`\{\{lang-javascript\}\}x === "Hello"` & strict comparison \tn 
% Row Count 6 (+ 2)
% Row 3
\SetRowColor{white}
`\{\{lang-javascript\}\}\&\&` & logical AND \tn 
% Row Count 7 (+ 1)
% Row 4
\SetRowColor{LightBackground}
`\{\{lang-javascript\}\}||` & logical OR \tn 
% Row Count 8 (+ 1)
% Row 5
\SetRowColor{white}
`\{\{lang-javascript\}\}!` & logical negation \tn 
% Row Count 10 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{6.8 cm} x{1.2 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{Data Types}}  \tn
% Row 0
\SetRowColor{LightBackground}
`\{\{lang-javascript\}\}let num = 10;` & \seqsplit{Number} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
`\{\{lang-javascript\}\}let str = "Hello";` & \seqsplit{String} \tn 
% Row Count 3 (+ 2)
% Row 2
\SetRowColor{LightBackground}
`\{\{lang-javascript\}\}let isTrue = true` & \seqsplit{Boolean} \tn 
% Row Count 5 (+ 2)
% Row 3
\SetRowColor{white}
`\{\{lang-javascript\}\}let arr = {[}1, 2, 3{]}` & Array \tn 
% Row Count 7 (+ 2)
% Row 4
\SetRowColor{LightBackground}
`\{\{lang-javascript\}\}let obj = \{ a:1, b:2, c:"three" \}` & \seqsplit{Object} \tn 
% Row Count 9 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{4.64 cm} x{3.36 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{Array}}  \tn
% Row 0
\SetRowColor{LightBackground}
`\{\{lang-javascript\}\}let array = {[}"a","b","c"{]}` & array definition \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
`\{\{lang-javascript\}\}array.length //3` & number of elements in array \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
`\{\{lang-javascript\}\}array{[}0{]} // a` & access first element \tn 
% Row Count 6 (+ 2)
% Row 3
\SetRowColor{white}
`\{\{lang-javascript\}\}array{[}n{]} //0=\textless{}n\textless{}array.length` & access n\textasciicircum{}th\textasciicircum{} element \tn 
% Row Count 9 (+ 3)
% Row 4
\SetRowColor{LightBackground}
`\{\{lang-javascript\}\}array{[}4{]} // error` & 4 grater then length of array \tn 
% Row Count 11 (+ 2)
% Row 5
\SetRowColor{white}
`\{\{lang-javascript\}\}array{[}array.length - 1{]} // c` & access last element \tn 
% Row Count 14 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{8.4cm}}{\bf\textcolor{white}{Comments}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{8.4cm}}{`\{\{lang-javascript\}\}// this is a one line comment`} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
\mymulticolumn{1}{x{8.4cm}}{`\{\{lang-javascript\}\}/* this is a multiple \{\{nl\}\}    lines comment \{\{nl\}\}    also called block comment */`} \tn 
% Row Count 4 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{8.4cm}}{\bf\textcolor{white}{Object}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{8.4cm}}{\{\{lang-javascript\}\}let object = \{ \newline    name: "Alice", \newline    age: 30 \newline \}} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{8.4cm}}{Unlike JSON, a JavaScript object does not have double quotes (") in the property name}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{4.96 cm} x{3.04 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{Object usage}}  \tn
% Row 0
\SetRowColor{LightBackground}
`\{\{lang-javascript\}\}object.name // Alice` & dot notation \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
`\{\{lang-javascript\}\}object{[}"name"{]} // Alice` & property access notation \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{8.4cm}}{`\{\{lang-javascript\}\}object.age // 30`} \tn 
% Row Count 5 (+ 1)
% Row 3
\SetRowColor{white}
`\{\{lang-javascript\}\}object.gender // undefined` & non-existent property \tn 
% Row Count 7 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{8.4cm}}{\bf\textcolor{white}{try...catch...finally}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{8.4cm}}{\{\{lang-javscript\}\}try\{ \newline    //code might throw an error \newline \} catch(err) \{ \newline    console.error("Error occurred", err.message); \newline \} finally \{ \newline    console.log("Operation completed"); \newline \}} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{8.4cm}}{try: This block contains code that might throw an exception (an error) \newline catch: This block handles the exception if an error occurs in the try block \newline finally: This block always executes, regardless of whether an error occurs or not}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{8.4cm}}{\bf\textcolor{white}{Function}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{8.4cm}}{\{\{lang-javascript\}\}function greet() \{ \newline    console.log("Hello") \newline \}} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{8.4cm}}{function definition}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{8.4cm}}{\bf\textcolor{white}{Function with parameter}}  \tn
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{8.4cm}}{\{\{lang-javascript\}\}function greet(name="Alice") \{ \newline    console.log("Hello") \newline \}} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{8.4cm}}{parameter name with default value "Alice"}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}


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

\end{document}