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<!DOCTYPE html><html lang="en"><head><link rel="stylesheet" href="./style.css"><title>Type - 30 seconds of code</title><meta charset="utf-8"><meta name="description" content="Curated collection of useful Javascript snippets that you can understand in 30 seconds or less."><meta name="keywords" content="javascript, snippets, code, programming"><meta name="author" content="Angelos Chalaris (chalarangelo@gmail.com)"><meta name="viewport" content="width=device-width,initial-scale=1"><meta name="theme-color" content="#111"><meta property="og:title" content="30 seconds of code"><meta property="og:description" content="Curated collection of useful Javascript snippets that you can understand in 30 seconds or less."/><meta property="og:type" content="website"/><meta property="og:image" content="https://30secondsofcode.org/logos/logo_512.png"><link rel="icon" type="image/png" href="./logos/logo_128.png"><link rel="manifest" href="manifest.json"><script>const search = (node) => {
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}</script></head><body onload="loader()" class="card-page"><a href="https://github.com/30-seconds/30-seconds-of-code" class="github-corner" aria-label="View source on Github"><svg width="56" height="56" viewBox="0 0 250 250" style="fill:#009688;color:#fff;position:fixed;top:0;border:0;right:0;z-index:1000" aria-hidden="true"><path d="M0,0 L115,115 L130,115 L142,142 L250,250 L250,0 Z"></path><path d="M128.3,109.0 C113.8,99.7 119.0,89.6 119.0,89.6 C122.0,82.7 120.5,78.6 120.5,78.6 C119.2,72.0 123.4,76.3 123.4,76.3 C127.3,80.9 125.5,87.3 125.5,87.3 C122.9,97.6 130.6,101.9 134.4,103.2" fill="currentColor" style="transform-origin:130px 106px" class="octo-arm"></path><path d="M115.0,115.0 C114.9,115.1 118.7,116.5 119.8,115.4 L133.7,101.6 C136.9,99.2 139.9,98.4 142.2,98.6 C133.8,88.0 127.5,74.4 143.8,58.0 C148.5,53.4 154.0,51.2 159.7,51.0 C160.3,49.4 163.2,43.6 171.4,40.1 C171.4,40.1 176.1,42.5 178.8,56.2 C183.1,58.6 187.2,61.8 190.9,65.4 C194.5,69.0 197.7,73.2 200.1,77.6 C213.8,80.2 216.3,84.9 216.3,84.9 C212.7,93.1 206.9,96.0 205.4,96.6 C205.1,102.4 203.0,107.8 198.3,112.5 C181.9,128.9 168.3,122.5 157.7,114.1 C157.9,116.9 156.7,120.9 152.7,124.9 L141.0,136.5 C139.8,137.7 141.6,141.9 141.8,141.8 Z" fill="currentColor" class="octo-body"></path></svg></a><button class="menu-button"></button><header><h1 class="logo"><a href="./index"><img src="https://30secondsofcode.org/logos/logo_256.png" alt="logo"/><span id="title">&nbsp;30 seconds of code</span> <small>Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.</small></a></h1></header><div class="container card-container"><input class="search" type="search" id="searchInput" onkeyup="search(this)" placeholder="Search..." aria-label="Snippet search"><nav><h4 class="collapse">Adapter</h4><ul><li><a tags="adapter,function,intermediate" href="./adapter#ary">ary</a></li><li><a tags="adapter,function,intermediate" href="./adapter#call">call</a></li><li><a tags="adapter,function,array,intermediate" href="./adapter#collectinto">collectInto</a></li><li><a tags="adapter,function,intermediate" href="./adapter#flip">flip</a></li><li><a tags="adapter,function,intermediate" href="./adapter#over">over</a></li><li><a tags="adapter,function,intermediate" href="./adapter#overargs">overArgs</a></li><li><a tags="adapter,function,promise,intermediate" href="./adapter#pipeasyncfunctions">pipeAsyncFunctions</a></li><li><a tags="adapter,function,intermediate" href="./adapter#pipefunctions">pipeFunctions</a></li><li><a tags="adapter,function,promise,intermediate" href="./adapter#promisify">promisify</a></li><li><a tags="adapter,function,intermediate" href="./adapter#rearg">rearg</a></li><li><a tags="adapter,intermediate" href="./adapter#spreadover">spreadOver</a></li><li><a tags="adapter,function,intermediate" href="./adapter#unary">unary</a></li></ul><h4 class="collapse">Array</h4><ul><li><a tags="array,function,beginner" href="./index#all">all</a></li><li><a tags="array,function,beginner" href="./index#allequal">allEqual</a></li><li><a tags="array,function,beginner" href="./index#any">any</a></li><li><a tags="array,string,utility,intermediate" href="./index#arraytocsv">arrayToCSV</a></li><li><a tags="array,intermediate" href="./index#bifurcate">bifurcate</a></li><li><a tags="array,function,intermediate" href="./index#bifurcateby">bifurcateBy</a></li><li><a tags="array,intermediate" href="./index#chunk">chunk</a></li><li><a tags="array,beginner" href="./index#compact">compact</a></li><li><a tags="array,object,intermediate" href="./index#countby">countBy</a></li><li><a tags="array,intermediate" href="./index#countoccurrences">countOccurrences</a></li><li><a tags="array,recursion,intermediate" href="./index#deepflatten">deepFlatten</a></li><li><a tags="array,math,beginner" href="./index#difference">difference</a></li><li><a tags="array,function,intermediate" href="./index#differenceby">differenceBy</a></li><li><a tags="array,function,intermediate" href="./index#differencewith">differenceWith</a></li><li><a tags="array,beginner" href="./index#drop">drop</a></li><li><a tags="array,beginner" href="./index#dropright">dropRight</a></li><li><a tags="array,function,intermediate" href="./index#droprightwhile">dropRightWhile</a></li><li><a tags="array,function,intermediate" href="./index#dropwhile">dropWhile</a></li><li><a tags="array,beginner" href="./index#everynth">everyNth</a></li><li><a tags="array,beginner" href="./index#filterfalsy">filterFalsy</a></li><li><a tags="array,beginner" href="./index#filternonunique">filterNonUnique</a></li><li><a tags="array,function,intermediate" href="./index#filternonuniqueby">filterNonUniqueBy</a></li><li><a tags="array,beginner" href="./index#findlast">findLast</a></li><li><a tags="array,function,intermediate" href="./index#findlastindex">findLastIndex</a></li><li><a tags="array,intermediate" href="./index#flatten">flatten</a></li><li><a tags="array,function,intermediate" href="./index#foreachright">forEachRight</a></li><li><a tags="array,object,intermediate" href="./index#groupby">groupBy</a></li><li><a tags="array,beginner" href="./index#head">head</a></li><li><a tags="array,intermediate" href="./index#indexofall">indexOfAll</a></li><li><a tags="array,beginner" href="./index#initial">initial</a></li><li><a tags="array,intermediate" href="./index#initialize2darray">initialize2DArray</a></li><li><a tags="array,math,intermediate" href="./index#initializearraywithrange">initializeArrayWithRange</a></li><li><a tags="array,math,intermediate" href="./index#initializearraywithrangeright">initializeArrayWithRangeRight</a></li><li><a tags="array,math,intermediate" href="./index#initializearraywithvalues">initializeArrayWithValues</a></li><li><a tags="array,recursion,intermediate" href="./index#initializendarray">initializeNDArray</a></li><li><a tags="array,math,intermediate" href="./index#intersection">intersection</a></li><li><a tags="array,function,intermediate" href="./index#intersectionby">intersectionBy</a></li><li><a tags="array,function,intermediate" href="./index#intersectionwith">intersectionWith</a></li><li><a tags="array,intermediate" href="./index#issorted">isSorted</a></li><li><a tags="array,intermediate" href="./index#join">join</a></li><li><a tags="array,string,object,advanced" href="./index#jsontocsv">JSONtoCSV</a></li><li><a tags="array,beginner" href="./index#last">last</a></li><li><a tags="array,string,utility,intermediate" href="./index#longestitem">longestItem</a></li><li><a tags="array,object,advanced" href="./index#mapobject">mapObject</a></li><li><a tags="array,math,beginner" href="./index#maxn">maxN</a></li><li><a tags="array,math,beginner" href="./index#minn">minN</a></li><li><a tags="array,function,beginner" href="./index#none">none</a></li><li><a tags="array,beginner" href="./index#nthelement">nthElement</a></li><li><a tags="array,beginner" href="./index#offset">offset</a></li><li><a tags="array,object,function,intermediate" href="./index#partition">partition</a></li><li><a tags="array,recursion,advanced" href="./index#permutations">permutations</a></li><li><a tags="array,intermediate" href="./index#pull">pull</a></li><li><a tags="array,advanced" href="./index#pullatindex">pullAtIndex</a></li><li><a tags="array,advanced" href="./index#pullatvalue">pullAtValue</a></li><li><a tags="array,function,advanced" href="./index#pullby">pullBy</a></li><li><a tags="array,intermediate" href="./index#reducedfilter">reducedFilter</a></li><li><a tags="array,function,intermediate" href="./index#reducesuccessive">reduceSuccessive</a></li><li><a tags="array,function,intermediate" href="./index#reducewhich">reduceWhich</a></li><li><a tags="array,beginner" href="./index#reject">reject</a></li><li><a tags="array,intermediate" href="./index#remove">remove</a></li><li><a tags="array,random,beginner" href="./index#sample">sample</a></li><li><a tags="array,random,intermediate" href="./index#samplesize">sampleSize</a></li><li><a tags="array,intermediate" href="./index#shank">shank</a></li><li><a tags="array,random,intermediate" href="./index#shuffle">shuffle</a></li><li><a tags="array,math,beginner" href="./index#similarity">similarity</a></li><li><a tags="array,math,intermediate" href="./index#sortedindex">sortedIndex</a></li><li><a tags="array,math,function,intermediate" href="./index#sortedindexby">sortedIndexBy</a></li><li><a tags="array,math,intermediate" href="./index#sortedlastindex">sortedLastIndex</a></li><li><a tags="array,math,function,intermediate" href="./index#sortedlastindexby">sortedLastIndexBy</a></li><li><a tags="array,sort,advanced,intermediate" href="./index#stablesort">stableSort</a></li><li><a tags="array,math,intermediate" href="./index#symmetricdifference">symmetricDifference</a></li><li><a tags="array,function,intermediate" href="./index#symmetricdifferenceby">symmetricDifferenceBy</a></li><li><a tags="array,function,intermediate" href="./index#symmetricdifferencewith">symmetricDifferenceWith</a></li><li><a tags="array,beginner" href="./index#tail">tail</a></li><li><a tags="array,beginner" href="./index#take">take</a></li><li><a tags="array,intermediate" href="./index#takeright">takeRight</a></li><li><a tags="array,function,intermediate" href="./index#takerightwhile">takeRightWhile</a></li><li><a tags="array,function,intermediate" href="./index#takewhile">takeWhile</a></li><li><a tags="array,intermediate" href="./index#tohash">toHash</a></li><li><a tags="array,math,beginner" href="./index#union">union</a></li><li><a tags="array,function,intermediate" href="./index#unionby">unionBy</a></li><li><a tags="array,function,intermediate" href="./index#unionwith">unionWith</a></li><li><a tags="array,beginner" href="./index#uniqueelements">uniqueElements</a></li><li><a tags="array,function,intermediate" href="./index#uniqueelementsby">uniqueElementsBy</a></li><li><a tags="array,function,intermediate" href="./index#uniqueelementsbyright">uniqueElementsByRight</a></li><li><a tags="array,math,intermediate" href="./index#uniquesymmetricdifference">uniqueSymmetricDifference</a></li><li><a tags="array,intermediate" href="./index#unzip">unzip</a></li><li><a tags="array,function,advanced" href="./index#unzipwith">unzipWith</a></li><li><a tags="array,beginner" href="./index#without">without</a></li><li><a tags="array,math,intermediate" href="./index#xprod">xProd</a></li><li><a tags="array,intermediate" href="./index#zip">zip</a></li><li><a tags="array,object,intermediate" href="./index#zipobject">zipObject</a></li><li><a tags="array,function,advanced" href="./index#zipwith">zipWith</a></li></ul><h4 class="collapse">Browser</h4><ul><li><a tags="browser,array,intermediate" href="./browser#arraytohtmllist">arrayToHtmlList</a></li><li><a tags="browser,intermediate" href="./browser#bottomvisible">bottomVisible</a></li><li><a tags="browser,string,advanced" href="./browser#copytoclipboard">copyToClipboard</a></li><li><a tags="browser,advanced" href="./browser#counter">counter</a></li><li><a tags="browser,utility,beginner" href="./browser#createelement">createElement</a></li><li><a tags="browser,event,advanced" href="./browser#createeventhub">createEventHub</a></li><li><a tags="browser,url,beginner" href="./browser#currenturl">currentURL</a></li><li><a tags="browser,intermediate" href="./browser#detectdevicetype">detectDeviceType</a></li><li><a tags="browser,intermediate" href="./browser#elementcontains">elementContains</a></li><li><a tags="browser,advanced" href="./browser#elementisvisibleinviewport">elementIsVisibleInViewport</a></li><li><a tags="browser,object,intermediate" href="./browser#formtoobject">formToObject</a></li><li><a tags="browser,beginner" href="./browser#getimages">getImages</a></li><li><a tags="browser,intermediate" href="./browser#getscrollposition">getScrollPosition</a></li><li><a tags="browser,css,beginner" href="./browser#getstyle">getStyle</a></li><li><a tags="browser,css,beginner" href="./browser#hasclass">hasClass</a></li><li><a tags="browser,utility,advanced,promise,advanced" href="./browser#hashbrowser">hashBrowser</a></li><li><a tags="browser,css,beginner" href="./browser#hide">hide</a></li><li><a tags="browser,url,intermediate" href="./browser#httpsredirect">httpsRedirect</a></li><li><a tags="browser,beginner" href="./browser#insertafter">insertAfter</a></li><li><a tags="browser,beginner" href="./browser#insertbefore">insertBefore</a></li><li><a tags="browser,beginner" href="./browser#isbrowsertabfocused">isBrowserTabFocused</a></li><li><a tags="browser,array,beginner" href="./browser#nodelisttoarray">nodeListToArray</a></li><li><a tags="browser,event,advanced" href="./browser#observemutations">observeMutations</a></li><li><a tags="browser,event,intermediate" href="./browser#off">off</a></li><li><a tags="browser,event,intermediate" href="./browser#on">on</a></li><li><a tags="browser,event,advanced" href="./browser#onuserinputchange">onUserInputChange</a></li><li><a tags="browser,utility,intermediate" href="./browser#prefix">prefix</a></li><li><a tags="browser,utility,intermediate" href="./browser#recordanimationframes">recordAnimationFrames</a></li><li><a tags="browser,url,beginner" href="./browser#redirect">redirect</a></li><li><a tags="browser,function,advanced,promise,url" href="./browser#runasync">runAsync</a></li><li><a tags="browser,intermediate" href="./browser#scrolltotop">scrollToTop</a></li><li><a tags="browser,string,intermediate" href="./browser#serializeform">serializeForm</a></li><li><a tags="browser,beginner" href="./browser#setstyle">setStyle</a></li><li><a tags="browser,css,beginner" href="./browser#show">show</a></li><li><a tags="browser,css,intermediate" href="./browser#smoothscroll">smoothScroll</a></li><li><a tags="browser,beginner" href="./browser#toggleclass">toggleClass</a></li><li><a tags="browser,event,intermediate" href="./browser#triggerevent">triggerEvent</a></li><li><a tags="browser,utility,random,intermediate" href="./browser#uuidgeneratorbrowser">UUIDGeneratorBrowser</a></li></ul><h4 class="collapse">Date</h4><ul><li><a tags="date,beginner" href="./date#dayofyear">dayOfYear</a></li><li><a tags="date,math,string,utility,intermediate" href="./date#formatduration">formatDuration</a></li><li><a tags="date,intermediate" href="./date#getcolontimefromdate">getColonTimeFromDate</a></li><li><a tags="date,intermediate" href="./date#getdaysdiffbetweendates">getDaysDiffBetweenDates</a></li><li><a tags="date,beginner" href="./date#getmeridiemsuffixofinteger">getMeridiemSuffixOfInteger</a></li><li><a tags="date,utility,beginner" href="./date#isafterdate">isAfterDate</a></li><li><a tags="date,utility,beginner" href="./date#isbeforedate">isBeforeDate</a></li><li><a tags="date,utility,beginner" href="./date#issamedate">isSameDate</a></li><li><a tags="date,beginner" href="./date#isweekday">isWeekday</a></li><li><a tags="date,beginner" href="./date#isweekend">isWeekend</a></li><li><a tags="date,math,beginner" href="./date#maxdate">maxDate</a></li><li><a tags="date,math,beginner" href="./date#mindate">minDate</a></li><li><a tags="date,intermediate" href="./date#tomorrow">tomorrow</a></li><li><a tags="date,intermediate" href="./date#yesterday">yesterday</a></li></ul><h4 class="collapse">Function</h4><ul><li><a tags="function,intermediate" href="./function#attempt">attempt</a></li><li><a tags="function,object,intermediate" href="./function#bind">bind</a></li><li><a tags="function,object,intermediate" href="./function#bindkey">bindKey</a></li><li><a tags="function,intermediate" href="./function#chainasync">chainAsync</a></li><li><a tags="function,object,utility,beginner" href="./function#checkprop">checkProp</a></li><li><a tags="function,intermediate" href="./function#compose">compose</a></li><li><a tags="function,intermediate" href="./function#composeright">composeRight</a></li><li><a tags="function,intermediate" href="./function#converge">converge</a></li><li><a tags="function,recursion,intermediate" href="./function#curry">curry</a></li><li><a tags="function,intermediate" href="./function#debounce">debounce</a></li><li><a tags="function,intermediate" href="./function#defer">defer</a></li><li><a tags="function,intermediate" href="./function#delay">delay</a></li><li><a tags="function,utility,beginner" href="./function#functionname">functionName</a></li><li><a tags="function,intermediate" href="./function#hz">hz</a></li><li><a tags="function,advanced" href="./function#memoize">memoize</a></li><li><a tags="function,beginner" href="./function#negate">negate</a></li><li><a tags="function,intermediate" href="./function#once">once</a></li><li><a tags="function,intermediate" href="./function#partial">partial</a></li><li><a tags="function,intermediate" href="./function#partialright">partialRight</a></li><li><a tags="function,promise,intermediate" href="./function#runpromisesinseries">runPromisesInSeries</a></li><li><a tags="function,promise,intermediate" href="./function#sleep">sleep</a></li><li><a tags="function,advanced" href="./function#throttle">throttle</a></li><li><a tags="function,intermediate" href="./function#times">times</a></li><li><a tags="function,intermediate" href="./function#uncurry">uncurry</a></li><li><a tags="function,array,intermediate" href="./function#unfold">unfold</a></li><li><a tags="function,intermediate" href="./function#when">when</a></li></ul><h4 class="collapse">Math</h4><ul><li><a tags="math,beginner" href="./math#approximatelyequal">approximatelyEqual</a></li><li><a tags="math,array,beginner" href="./math#average">average</a></li><li><a tags="math,array,function,intermediate" href="./math#averageby">averageBy</a></li><li><a tags="math,intermediate" href="./math#binomialcoefficient">binomialCoefficient</a></li><li><a tags="math,beginner" href="./math#clampnumber">clampNumber</a></li><li><a tags="math,beginner" href="./math#degreestorads">degreesToRads</a></li><li><a tags="math,array,beginner" href="./math#digitize">digitize</a></li><li><a tags="math,beginner" href="./math#distance">distance</a></li><li><a tags="math,array,advanced" href="./math#elo">elo</a></li><li><a tags="math,recursion,beginner" href="./math#factorial">factorial</a></li><li><a tags="math,array,beginner" href="./math#fibonacci">fibonacci</a></li><li><a tags="math,recursion,beginner" href="./math#gcd">gcd</a></li><li><a tags="math,intermediate" href="./math#geometricprogression">geometricProgression</a></li><li><a tags="math,beginner" href="./math#hammingdistance">hammingDistance</a></li><li><a tags="math,beginner" href="./math#inrange">inRange</a></li><li><a tags="math,beginner" href="./math#isdivisible">isDivisible</a></li><li><a tags="math,beginner" href="./math#iseven">isEven</a></li><li><a tags="math,utility,beginner" href="./math#isnegativezero">isNegativeZero</a></li><li><a tags="math,beginner,intermediate" href="./math#isprime">isPrime</a></li><li><a tags="math,recursion,beginner" href="./math#lcm">lcm</a></li><li><a tags="math,utility,advanced" href="./math#luhncheck">luhnCheck</a></li><li><a tags="math,beginner" href="./math#mapnumrange">mapNumRange</a></li><li><a tags="math,array,function,beginner" href="./math#maxby">maxBy</a></li><li><a tags="math,array,intermediate" href="./math#median">median</a></li><li><a tags="math,array,beginner" href="./math#midpoint">midpoint</a></li><li><a tags="math,array,function,beginner" href="./math#minby">minBy</a></li><li><a tags="math,intermediate" href="./math#percentile">percentile</a></li><li><a tags="math,beginner" href="./math#powerset">powerset</a></li><li><a tags="math,array,intermediate" href="./math#primes">primes</a></li><li><a tags="math,beginner" href="./math#radstodegrees">radsToDegrees</a></li><li><a tags="math,utility,random,intermediate" href="./math#randomintarrayinrange">randomIntArrayInRange</a></li><li><a tags="math,utility,random,beginner" href="./math#randomintegerinrange">randomIntegerInRange</a></li><li><a tags="math,utility,random,beginner" href="./math#randomnumberinrange">randomNumberInRange</a></li><li><a tags="math,intermediate" href="./math#round">round</a></li><li><a tags="math,utility,intermediate" href="./math#sdbm">sdbm</a></li><li><a tags="math,array,intermediate" href="./math#standarddeviation">standardDeviation</a></li><li><a tags="math,array,beginner" href="./math#sum">sum</a></li><li><a tags="math,array,function,intermediate" href="./math#sumby">sumBy</a></li><li><a tags="math,intermediate" href="./math#sumpower">sumPower</a></li><li><a tags="math,beginner" href="./math#tosafeinteger">toSafeInteger</a></li><li><a tags="math,beginner" href="./math#vectordistance">vectorDistance</a></li></ul><h4 class="collapse">Node</h4><ul><li><a tags="node,string,utility,beginner" href="./node#atob">atob</a></li><li><a tags="node,string,utility,beginner" href="./node#btoa">btoa</a></li><li><a tags="node,utility,string,intermediate" href="./node#colorize">colorize</a></li><li><a tags="node,beginner" href="./node#createdirifnotexists">createDirIfNotExists</a></li><li><a tags="node,intermediate" href="./node#hasflags">hasFlags</a></li><li><a tags="node,utility,promise,intermediate" href="./node#hashnode">hashNode</a></li><li><a tags="node,type,intermediate" href="./node#isduplexstream">isDuplexStream</a></li><li><a tags="node,type,intermediate" href="./node#isreadablestream">isReadableStream</a></li><li><a tags="node,type,intermediate" href="./node#isstream">isStream</a></li><li><a tags="node,intermediate" href="./node#istravisci">isTravisCI</a></li><li><a tags="node,type,intermediate" href="./node#iswritablestream">isWritableStream</a></li><li><a tags="node,json,intermediate" href="./node#jsontofile">JSONToFile</a></li><li><a tags="node,array,string,beginner" href="./node#readfilelines">readFileLines</a></li><li><a tags="node,string,beginner" href="./node#untildify">untildify</a></li><li><a tags="node,utility,random,intermediate" href="./node#uuidgeneratornode">UUIDGeneratorNode</a></li></ul><h4 class="collapse">Object</h4><ul><li><a tags="object,function,intermediate" href="./object#bindall">bindAll</a></li><li><a tags="object,recursion,intermediate" href="./object#deepclone">deepClone</a></li><li><a tags="object,recursion,intermediate" href="./object#deepfreeze">deepFreeze</a></li><li><a tags="object,intermediate" href="./object#deepget">deepGet</a></li><li><a tags="object,recursion,advanced" href="./object#deepmapkeys">deepMapKeys</a></li><li><a tags="object,intermediate" href="./object#defaults">defaults</a></li><li><a tags="object,recursion,intermediate" href="./object#dig">dig</a></li><li><a tags="object,array,type,advanced" href="./object#equals">equals</a></li><li><a tags="object,function,intermediate" href="./object#findkey">findKey</a></li><li><a tags="object,function,intermediate" href="./object#findlastkey">findLastKey</a></li><li><a tags="object,recursion,intermediate" href="./object#flattenobject">flattenObject</a></li><li><a tags="object,intermediate" href="./object#forown">forOwn</a></li><li><a tags="object,intermediate" href="./object#forownright">forOwnRight</a></li><li><a tags="object,function,intermediate" href="./object#functions">functions</a></li><li><a tags="object,intermediate" href="./object#get">get</a></li><li><a tags="object,function,intermediate" href="./object#invertkeyvalues">invertKeyValues</a></li><li><a tags="object,intermediate" href="./object#lowercasekeys">lowercaseKeys</a></li><li><a tags="object,function,intermediate" href="./object#mapkeys">mapKeys</a></li><li><a tags="object,function,intermediate" href="./object#mapvalues">mapValues</a></li><li><a tags="object,type,intermediate" href="./object#matches">matches</a></li><li><a tags="object,type,function,intermediate" href="./object#matcheswith">matchesWith</a></li><li><a tags="object,array,intermediate" href="./object#merge">merge</a></li><li><a tags="object,intermediate" href="./object#nest">nest</a></li><li><a tags="object,array,beginner" href="./object#objectfrompairs">objectFromPairs</a></li><li><a tags="object,array,beginner" href="./object#objecttopairs">objectToPairs</a></li><li><a tags="object,array,intermediate" href="./object#omit">omit</a></li><li><a tags="object,array,function,intermediate" href="./object#omitby">omitBy</a></li><li><a tags="object,array,intermediate" href="./object#orderby">orderBy</a></li><li><a tags="object,array,intermediate" href="./object#pick">pick</a></li><li><a tags="object,array,function,intermediate" href="./object#pickby">pickBy</a></li><li><a tags="object,intermediate" href="./object#renamekeys">renameKeys</a></li><li><a tags="object,beginner" href="./object#shallowclone">shallowClone</a></li><li><a tags="object,array,string,intermediate" href="./object#size">size</a></li><li><a tags="object,array,intermediate" href="./object#transform">transform</a></li><li><a tags="object,logic,array,intermediate" href="./object#truthcheckcollection">truthCheckCollection</a></li><li><a tags="object,advanced" href="./object#unflattenobject">unflattenObject</a></li></ul><h4 class="collapse">String</h4><ul><li><a tags="string,beginner" href="./string#bytesize">byteSize</a></li><li><a tags="string,array,intermediate" href="./string#capitalize">capitalize</a></li><li><a tags="string,regexp,intermediate" href="./string#capitalizeeveryword">capitalizeEveryWord</a></li><li><a tags="string,regexp,beginner" href="./string#compactwhitespace">compactWhitespace</a></li><li><a tags="string,array,utility,intermediate" href="./string#csvtoarray">CSVToArray</a></li><li><a tags="string,array,object,advanced" href="./string#csvtojson">CSVToJSON</a></li><li><a tags="string,array,intermediate" href="./string#decapitalize">decapitalize</a></li><li><a tags="string,browser,regexp,intermediate" href="./string#escapehtml">escapeHTML</a></li><li><a tags="string,regexp,intermediate" href="./string#escaperegexp">escapeRegExp</a></li><li><a tags="string,intermediate" href="./string#fromcamelcase">fromCamelCase</a></li><li><a tags="string,utility,beginner" href="./string#indentstring">indentString</a></li><li><a tags="string,utility,browser,url,intermediate" href="./string#isabsoluteurl">isAbsoluteURL</a></li><li><a tags="string,regexp,intermediate" href="./string#isanagram">isAnagram</a></li><li><a tags="string,utility,beginner" href="./string#islowercase">isLowerCase</a></li><li><a tags="string,utility,beginner" href="./string#isuppercase">isUpperCase</a></li><li><a tags="string,array,function,utility,beginner" href="./string#mapstring">mapString</a></li><li><a tags="string,utility,regexp,intermediate" href="./string#mask">mask</a></li><li><a tags="string,beginner" href="./string#pad">pad</a></li><li><a tags="string,intermediate" href="./string#palindrome">palindrome</a></li><li><a tags="string,intermediate" href="./string#pluralize">pluralize</a></li><li><a tags="string,regexp,intermediate" href="./string#removenonascii">removeNonASCII</a></li><li><a tags="string,array,beginner" href="./string#reversestring">reverseString</a></li><li><a tags="string,beginner" href="./string#sortcharactersinstring">sortCharactersInString</a></li><li><a tags="string,beginner" href="./string#splitlines">splitLines</a></li><li><a tags="string,recursion,advanced" href="./string#stringpermutations">stringPermutations</a></li><li><a tags="string,utility,regexp,beginner" href="./string#striphtmltags">stripHTMLTags</a></li><li><a tags="string,regexp,intermediate" href="./string#tocamelcase">toCamelCase</a></li><li><a tags="string,regexp,intermediate" href="./string#tokebabcase">toKebabCase</a></li><li><a tags="string,regexp,intermediate" href="./string#tosnakecase">toSnakeCase</a></li><li><a tags="string,regepx,intermediate" href="./string#totitlecase">toTitleCase</a></li><li><a tags="string,beginner" href="./string#truncatestring">truncateString</a></li><li><a tags="string,browser,beginner" href="./string#unescapehtml">unescapeHTML</a></li><li><a tags="string,utility,regexp,advanced" href="./string#urljoin">URLJoin</a></li><li><a tags="string,regexp,intermediate" href="./string#words">words</a></li></ul><h4 class="collapse">Type</h4><ul><li><a tags="type,beginner" href="#gettype">getType</a></li><li><a tags="type,array,regexp,beginner" href="#is">is</a></li><li><a tags="type,array,intermediate" href="#isarraylike">isArrayLike</a></li><li><a tags="type,beginner" href="#isboolean">isBoolean</a></li><li><a tags="type,array,object,string,beginner" href="#isempty">isEmpty</a></li><li><a tags="type,function,beginner" href="#isfunction">isFunction</a></li><li><a tags="type,beginner" href="#isnil">isNil</a></li><li><a tags="type,beginner" href="#isnull">isNull</a></li><li><a tags="type,math,beginner" href="#isnumber">isNumber</a></li><li><a tags="type,object,beginner" href="#isobject">isObject</a></li><li><a tags="type,object,beginner" href="#isobjectlike">isObjectLike</a></li><li><a tags="type,object,intermediate" href="#isplainobject">isPlainObject</a></li><li><a tags="type,function,array,string,intermediate" href="#isprimitive">isPrimitive</a></li><li><a tags="type,function,promise,intermediate" href="#ispromiselike">isPromiseLike</a></li><li><a tags="type,string,beginner" href="#isstring">isString</a></li><li><a tags="type,beginner" href="#issymbol">isSymbol</a></li><li><a tags="type,beginner" href="#isundefined">isUndefined</a></li><li><a tags="type,json,intermediate" href="#isvalidjson">isValidJSON</a></li></ul><h4 class="collapse">Utility</h4><ul><li><a tags="utility,array,type,beginner" href="./utility#castarray">castArray</a></li><li><a tags="utility,regexp,intermediate" href="./utility#cloneregexp">cloneRegExp</a></li><li><a tags="utility,beginner" href="./utility#coalesce">coalesce</a></li><li><a tags="utility,intermediate" href="./utility#coalescefactory">coalesceFactory</a></li><li><a tags="utility,string,intermediate" href="./utility#extendhex">extendHex</a></li><li><a tags="utility,browser,string,url,intermediate" href="./utility#geturlparameters">getURLParameters</a></li><li><a tags="utility,string,math,advanced" href="./utility#hextorgb">hexToRGB</a></li><li><a tags="utility,url,browser,intermediate" href="./utility#httpget">httpGet</a></li><li><a tags="utility,url,browser,intermediate" href="./utility#httppost">httpPost</a></li><li><a tags="utility,browser,intermediate" href="./utility#isbrowser">isBrowser</a></li><li><a tags="utility,function" href="./utility#mostperformant">mostPerformant</a></li><li><a tags="utility,function,beginner" href="./utility#ntharg">nthArg</a></li><li><a tags="utility,string,intermediate" href="./utility#parsecookie">parseCookie</a></li><li><a tags="utility,string,math,advanced" href="./utility#prettybytes">prettyBytes</a></li><li><a tags="utility,random,beginner" href="./utility#randomhexcolorcode">randomHexColorCode</a></li><li><a tags="utility,intermediate" href="./utility#rgbtohex">RGBToHex</a></li><li><a tags="utility,string,intermediate" href="./utility#serializecookie">serializeCookie</a></li><li><a tags="utility,beginner" href="./utility#timetaken">timeTaken</a></li><li><a tags="utility,intermediate" href="./utility#tocurrency">toCurrency</a></li><li><a tags="utility,math,beginner" href="./utility#todecimalmark">toDecimalMark</a></li><li><a tags="utility,math,intermediate" href="./utility#toordinalsuffix">toOrdinalSuffix</a></li><li><a tags="utility,math,intermediate" href="./utility#validatenumber">validateNumber</a></li><li><a tags="utility,regexp,intermediate" href="./utility#yesno">yesNo</a></li></ul><h4 class="static-link"><a href="./archive">Archive</a></h4><h4 class="static-link"><a href="./glossary">Glossary</a></h4><h4 class="static-link"><a href="./contributing">Contributing</a></h4><h4 class="static-link"><a href="./about">About</a></h4><div><button class="social fb"></button><button class="social instagram"></button><button class="social twitter"></button></div></nav><main class="col-centered"><span id="top"><br/><br/></span><h2 class="category-name">Type</h2><div class="card code-card"><div class="corner beginner" aria-label="beginner" title="beginner"></div><div class="section card-content"><h4 id="gettype">getType</h4><p>Returns the native type of a value.</p><p>Returns lowercased constructor name of value, <code>&quot;undefined&quot;</code> or <code>&quot;null&quot;</code> if value is <code>undefined</code> or <code>null</code>.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">getType</span> <span class="token operator">=</span> v <span class="token operator">=></span>
v <span class="token operator">===</span> undefined <span class="token operator">?</span> <span class="token string">'undefined'</span> <span class="token punctuation">:</span> v <span class="token operator">===</span> <span class="token keyword">null</span> <span class="token operator">?</span> <span class="token string">'null'</span> <span class="token punctuation">:</span> v<span class="token punctuation">.</span>constructor<span class="token punctuation">.</span>name<span class="token punctuation">.</span><span class="token function">toLowerCase</span><span class="token punctuation">();</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token function">getType</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">Set</span><span class="token punctuation">([</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">]));</span> <span class="token comment">// 'set'</span>
</pre></div><div class="card code-card"><div class="corner beginner" aria-label="beginner" title="beginner"></div><div class="section card-content"><h4 id="is">is</h4><p>Checks if the provided value is of the specified type.</p><p>Ensure the value is not <code>undefined</code> or <code>null</code> using <code>Array.prototype.includes()</code>, and compare the <code>constructor</code> property on the value with <code>type</code> to check if the provided value is of the specified <code>type</code>.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">is</span> <span class="token operator">=</span> <span class="token punctuation">(</span>type<span class="token punctuation">,</span> val<span class="token punctuation">)</span> <span class="token operator">=> !</span><span class="token punctuation">[,</span> <span class="token keyword">null</span><span class="token punctuation">].</span><span class="token function">includes</span><span class="token punctuation">(</span>val<span class="token punctuation">)</span> <span class="token operator">&amp;&amp;</span> val<span class="token punctuation">.</span>constructor <span class="token operator">===</span> type<span class="token punctuation">;</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token function">is</span><span class="token punctuation">(</span>Array<span class="token punctuation">, [</span><span class="token number">1</span><span class="token punctuation">]);</span> <span class="token comment">// true</span>
<span class="token function">is</span><span class="token punctuation">(</span>ArrayBuffer<span class="token punctuation">,</span> <span class="token keyword">new</span> <span class="token class-name">ArrayBuffer</span><span class="token punctuation">());</span> <span class="token comment">// true</span>
<span class="token function">is</span><span class="token punctuation">(</span>Map<span class="token punctuation">,</span> <span class="token keyword">new</span> <span class="token class-name">Map</span><span class="token punctuation">());</span> <span class="token comment">// true</span>
<span class="token function">is</span><span class="token punctuation">(</span>RegExp<span class="token punctuation">,</span> <span class="token regex">/./g</span><span class="token punctuation">);</span> <span class="token comment">// true</span>
<span class="token function">is</span><span class="token punctuation">(</span>Set<span class="token punctuation">,</span> <span class="token keyword">new</span> <span class="token class-name">Set</span><span class="token punctuation">());</span> <span class="token comment">// true</span>
<span class="token function">is</span><span class="token punctuation">(</span>WeakMap<span class="token punctuation">,</span> <span class="token keyword">new</span> <span class="token class-name">WeakMap</span><span class="token punctuation">());</span> <span class="token comment">// true</span>
<span class="token function">is</span><span class="token punctuation">(</span>WeakSet<span class="token punctuation">,</span> <span class="token keyword">new</span> <span class="token class-name">WeakSet</span><span class="token punctuation">());</span> <span class="token comment">// true</span>
<span class="token function">is</span><span class="token punctuation">(</span>String<span class="token punctuation">,</span> <span class="token string">''</span><span class="token punctuation">);</span> <span class="token comment">// true</span>
<span class="token function">is</span><span class="token punctuation">(</span>String<span class="token punctuation">,</span> <span class="token keyword">new</span> <span class="token class-name">String</span><span class="token punctuation">(</span><span class="token string">''</span><span class="token punctuation">));</span> <span class="token comment">// true</span>
<span class="token function">is</span><span class="token punctuation">(</span>Number<span class="token punctuation">,</span> <span class="token number">1</span><span class="token punctuation">);</span> <span class="token comment">// true</span>
<span class="token function">is</span><span class="token punctuation">(</span>Number<span class="token punctuation">,</span> <span class="token keyword">new</span> <span class="token class-name">Number</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">));</span> <span class="token comment">// true</span>
<span class="token function">is</span><span class="token punctuation">(</span>Boolean<span class="token punctuation">,</span> <span class="token boolean">true</span><span class="token punctuation">);</span> <span class="token comment">// true</span>
<span class="token function">is</span><span class="token punctuation">(</span>Boolean<span class="token punctuation">,</span> <span class="token keyword">new</span> <span class="token class-name">Boolean</span><span class="token punctuation">(</span><span class="token boolean">true</span><span class="token punctuation">));</span> <span class="token comment">// true</span>
</pre></div><div class="card code-card"><div class="corner intermediate" aria-label="intermediate" title="intermediate"></div><div class="section card-content"><h4 id="isarraylike">isArrayLike</h4><p>Checks if the provided argument is array-like (i.e. is iterable).</p><p>Check if the provided argument is not <code>null</code> and that its <code>Symbol.iterator</code> property is a function.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">isArrayLike</span> <span class="token operator">=</span> obj <span class="token operator">=></span> obj <span class="token operator">!=</span> <span class="token keyword">null</span> <span class="token operator">&amp;&amp;</span> <span class="token keyword">typeof</span> obj<span class="token punctuation">[</span>Symbol<span class="token punctuation">.</span>iterator<span class="token punctuation">]</span> <span class="token operator">===</span> <span class="token string">'function'</span><span class="token punctuation">;</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token function">isArrayLike</span><span class="token punctuation">(</span>document<span class="token punctuation">.</span><span class="token function">querySelectorAll</span><span class="token punctuation">(</span><span class="token string">'.className'</span><span class="token punctuation">));</span> <span class="token comment">// true</span>
<span class="token function">isArrayLike</span><span class="token punctuation">(</span><span class="token string">'abc'</span><span class="token punctuation">);</span> <span class="token comment">// true</span>
<span class="token function">isArrayLike</span><span class="token punctuation">(</span><span class="token keyword">null</span><span class="token punctuation">);</span> <span class="token comment">// false</span>
</pre></div><div class="card code-card"><div class="corner beginner" aria-label="beginner" title="beginner"></div><div class="section card-content"><h4 id="isboolean">isBoolean</h4><p>Checks if the given argument is a native boolean element.</p><p>Use <code>typeof</code> to check if a value is classified as a boolean primitive.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">isBoolean</span> <span class="token operator">=</span> val <span class="token operator">=></span> <span class="token keyword">typeof</span> val <span class="token operator">===</span> <span class="token string">'boolean'</span><span class="token punctuation">;</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token function">isBoolean</span><span class="token punctuation">(</span><span class="token keyword">null</span><span class="token punctuation">);</span> <span class="token comment">// false</span>
<span class="token function">isBoolean</span><span class="token punctuation">(</span><span class="token boolean">false</span><span class="token punctuation">);</span> <span class="token comment">// true</span>
</pre></div><div class="card code-card"><div class="corner beginner" aria-label="beginner" title="beginner"></div><div class="section card-content"><h4 id="isempty">isEmpty</h4><p>Returns true if the a value is an empty object, collection, has no enumerable properties or is any type that is not considered a collection.</p><p>Check if the provided value is <code>null</code> or if its <code>length</code> is equal to <code>0</code>.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">isEmpty</span> <span class="token operator">=</span> val <span class="token operator">=></span> val <span class="token operator">==</span> <span class="token keyword">null</span> <span class="token operator">|| !</span><span class="token punctuation">(</span>Object<span class="token punctuation">.</span><span class="token function">keys</span><span class="token punctuation">(</span>val<span class="token punctuation">)</span> <span class="token operator">||</span> val<span class="token punctuation">).</span>length<span class="token punctuation">;</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token function">isEmpty</span><span class="token punctuation">([]);</span> <span class="token comment">// true</span>
<span class="token function">isEmpty</span><span class="token punctuation">({});</span> <span class="token comment">// true</span>
<span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token string">''</span><span class="token punctuation">);</span> <span class="token comment">// true</span>
<span class="token function">isEmpty</span><span class="token punctuation">([</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">]);</span> <span class="token comment">// false</span>
<span class="token function">isEmpty</span><span class="token punctuation">({</span> a<span class="token punctuation">:</span> <span class="token number">1</span><span class="token punctuation">,</span> b<span class="token punctuation">:</span> <span class="token number">2</span> <span class="token punctuation">});</span> <span class="token comment">// false</span>
<span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token string">'text'</span><span class="token punctuation">);</span> <span class="token comment">// false</span>
<span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token number">123</span><span class="token punctuation">);</span> <span class="token comment">// true - type is not considered a collection</span>
<span class="token function">isEmpty</span><span class="token punctuation">(</span><span class="token boolean">true</span><span class="token punctuation">);</span> <span class="token comment">// true - type is not considered a collection</span>
</pre></div><div class="card code-card"><div class="corner beginner" aria-label="beginner" title="beginner"></div><div class="section card-content"><h4 id="isfunction">isFunction</h4><p>Checks if the given argument is a function.</p><p>Use <code>typeof</code> to check if a value is classified as a function primitive.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">isFunction</span> <span class="token operator">=</span> val <span class="token operator">=></span> <span class="token keyword">typeof</span> val <span class="token operator">===</span> <span class="token string">'function'</span><span class="token punctuation">;</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token function">isFunction</span><span class="token punctuation">(</span><span class="token string">'x'</span><span class="token punctuation">);</span> <span class="token comment">// false</span>
<span class="token function">isFunction</span><span class="token punctuation">(</span>x <span class="token operator">=></span> x<span class="token punctuation">);</span> <span class="token comment">// true</span>
</pre></div><div class="card code-card"><div class="corner beginner" aria-label="beginner" title="beginner"></div><div class="section card-content"><h4 id="isnil">isNil</h4><p>Returns <code>true</code> if the specified value is <code>null</code> or <code>undefined</code>, <code>false</code> otherwise.</p><p>Use the strict equality operator to check if the value and of <code>val</code> are equal to <code>null</code> or <code>undefined</code>.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">isNil</span> <span class="token operator">=</span> val <span class="token operator">=></span> val <span class="token operator">===</span> undefined <span class="token operator">||</span> val <span class="token operator">===</span> <span class="token keyword">null</span><span class="token punctuation">;</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token function">isNil</span><span class="token punctuation">(</span><span class="token keyword">null</span><span class="token punctuation">);</span> <span class="token comment">// true</span>
<span class="token function">isNil</span><span class="token punctuation">(</span>undefined<span class="token punctuation">);</span> <span class="token comment">// true</span>
</pre></div><div class="card code-card"><div class="corner beginner" aria-label="beginner" title="beginner"></div><div class="section card-content"><h4 id="isnull">isNull</h4><p>Returns <code>true</code> if the specified value is <code>null</code>, <code>false</code> otherwise.</p><p>Use the strict equality operator to check if the value and of <code>val</code> are equal to <code>null</code>.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">isNull</span> <span class="token operator">=</span> val <span class="token operator">=></span> val <span class="token operator">===</span> <span class="token keyword">null</span><span class="token punctuation">;</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token function">isNull</span><span class="token punctuation">(</span><span class="token keyword">null</span><span class="token punctuation">);</span> <span class="token comment">// true</span>
</pre></div><div class="card code-card"><div class="corner beginner" aria-label="beginner" title="beginner"></div><div class="section card-content"><h4 id="isnumber">isNumber</h4><p>Checks if the given argument is a number.</p><p>Use <code>typeof</code> to check if a value is classified as a number primitive. To safeguard against <code>NaN</code>, check if <code>val === val</code> (as <code>NaN</code> has a <code>typeof</code> equal to <code>number</code> and is the only value not equal to itself).</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">isNumber</span> <span class="token operator">=</span> val <span class="token operator">=></span> <span class="token keyword">typeof</span> val <span class="token operator">===</span> <span class="token string">'number'</span> <span class="token operator">&amp;&amp;</span> val <span class="token operator">===</span> val<span class="token punctuation">;</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token function">isNumber</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">);</span> <span class="token comment">// true</span>
<span class="token function">isNumber</span><span class="token punctuation">(</span><span class="token string">'1'</span><span class="token punctuation">);</span> <span class="token comment">// false</span>
<span class="token function">isNumber</span><span class="token punctuation">(</span><span class="token number">NaN</span><span class="token punctuation">);</span> <span class="token comment">// false</span>
</pre></div><div class="card code-card"><div class="corner beginner" aria-label="beginner" title="beginner"></div><div class="section card-content"><h4 id="isobject">isObject</h4><p>Returns a boolean determining if the passed value is an object or not.</p><p>Uses the <code>Object</code> constructor to create an object wrapper for the given value. If the value is <code>null</code> or <code>undefined</code>, create and return an empty object. Οtherwise, return an object of a type that corresponds to the given value.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">isObject</span> <span class="token operator">=</span> obj <span class="token operator">=></span> obj <span class="token operator">===</span> <span class="token function">Object</span><span class="token punctuation">(</span>obj<span class="token punctuation">);</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token function">isObject</span><span class="token punctuation">([</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">,</span> <span class="token number">4</span><span class="token punctuation">]);</span> <span class="token comment">// true</span>
<span class="token function">isObject</span><span class="token punctuation">([]);</span> <span class="token comment">// true</span>
<span class="token function">isObject</span><span class="token punctuation">([</span><span class="token string">'Hello!'</span><span class="token punctuation">]);</span> <span class="token comment">// true</span>
<span class="token function">isObject</span><span class="token punctuation">({</span> a<span class="token punctuation">:</span> <span class="token number">1</span> <span class="token punctuation">});</span> <span class="token comment">// true</span>
<span class="token function">isObject</span><span class="token punctuation">({});</span> <span class="token comment">// true</span>
<span class="token function">isObject</span><span class="token punctuation">(</span><span class="token boolean">true</span><span class="token punctuation">);</span> <span class="token comment">// false</span>
</pre></div><div class="card code-card"><div class="section card-content"><h4><a href="https://frontendmasters.com/courses/js-fundamentals-functional-v2/" target="_blank" rel="noopener noreferrer">Recommended Resource - JavaScript: From Fundamentals to Functional JS</a></h4><p>Learn higher-order functions, closures, scope, master key functional methods like map, reduce and filter and promises and ES6+ asynchronous JavaScript.</p></div></div><div class="card code-card"><div class="corner beginner" aria-label="beginner" title="beginner"></div><div class="section card-content"><h4 id="isobjectlike">isObjectLike</h4><p>Checks if a value is object-like.</p><p>Check if the provided value is not <code>null</code> and its <code>typeof</code> is equal to <code>'object'</code>.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">isObjectLike</span> <span class="token operator">=</span> val <span class="token operator">=></span> val <span class="token operator">!==</span> <span class="token keyword">null</span> <span class="token operator">&amp;&amp;</span> <span class="token keyword">typeof</span> val <span class="token operator">===</span> <span class="token string">'object'</span><span class="token punctuation">;</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token function">isObjectLike</span><span class="token punctuation">({});</span> <span class="token comment">// true</span>
<span class="token function">isObjectLike</span><span class="token punctuation">([</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">]);</span> <span class="token comment">// true</span>
<span class="token function">isObjectLike</span><span class="token punctuation">(</span>x <span class="token operator">=></span> x<span class="token punctuation">);</span> <span class="token comment">// false</span>
<span class="token function">isObjectLike</span><span class="token punctuation">(</span><span class="token keyword">null</span><span class="token punctuation">);</span> <span class="token comment">// false</span>
</pre></div><div class="card code-card"><div class="corner intermediate" aria-label="intermediate" title="intermediate"></div><div class="section card-content"><h4 id="isplainobject">isPlainObject</h4><p>Checks if the provided value is an object created by the Object constructor.</p><p>Check if the provided value is truthy, use <code>typeof</code> to check if it is an object and <code>Object.constructor</code> to make sure the constructor is equal to <code>Object</code>.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">isPlainObject</span> <span class="token operator">=</span> val <span class="token operator">=> !!</span>val <span class="token operator">&amp;&amp;</span> <span class="token keyword">typeof</span> val <span class="token operator">===</span> <span class="token string">'object'</span> <span class="token operator">&amp;&amp;</span> val<span class="token punctuation">.</span>constructor <span class="token operator">===</span> Object<span class="token punctuation">;</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token function">isPlainObject</span><span class="token punctuation">({</span> a<span class="token punctuation">:</span> <span class="token number">1</span> <span class="token punctuation">});</span> <span class="token comment">// true</span>
<span class="token function">isPlainObject</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">Map</span><span class="token punctuation">());</span> <span class="token comment">// false</span>
</pre></div><div class="card code-card"><div class="corner intermediate" aria-label="intermediate" title="intermediate"></div><div class="section card-content"><h4 id="isprimitive">isPrimitive</h4><p>Returns a boolean determining if the passed value is primitive or not.</p><p>Create an object from <code>val</code> and compare it with <code>val</code> to determine if the passed value is primitive (i.e. not equal to the created object).</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">isPrimitive</span> <span class="token operator">=</span> val <span class="token operator">=></span> <span class="token function">Object</span><span class="token punctuation">(</span>val<span class="token punctuation">)</span> <span class="token operator">!==</span> val<span class="token punctuation">;</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token function">isPrimitive</span><span class="token punctuation">(</span><span class="token keyword">null</span><span class="token punctuation">);</span> <span class="token comment">// true</span>
<span class="token function">isPrimitive</span><span class="token punctuation">(</span><span class="token number">50</span><span class="token punctuation">);</span> <span class="token comment">// true</span>
<span class="token function">isPrimitive</span><span class="token punctuation">(</span><span class="token string">'Hello!'</span><span class="token punctuation">);</span> <span class="token comment">// true</span>
<span class="token function">isPrimitive</span><span class="token punctuation">(</span><span class="token boolean">false</span><span class="token punctuation">);</span> <span class="token comment">// true</span>
<span class="token function">isPrimitive</span><span class="token punctuation">(</span><span class="token function">Symbol</span><span class="token punctuation">());</span> <span class="token comment">// true</span>
<span class="token function">isPrimitive</span><span class="token punctuation">([]);</span> <span class="token comment">// false</span>
</pre></div><div class="card code-card"><div class="corner intermediate" aria-label="intermediate" title="intermediate"></div><div class="section card-content"><h4 id="ispromiselike">isPromiseLike</h4><p>Returns <code>true</code> if an object looks like a <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise"><code>Promise</code></a>, <code>false</code> otherwise.</p><p>Check if the object is not <code>null</code>, its <code>typeof</code> matches either <code>object</code> or <code>function</code> and if it has a <code>.then</code> property, which is also a <code>function</code>.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">isPromiseLike</span> <span class="token operator">=</span> obj <span class="token operator">=></span>
obj <span class="token operator">!==</span> <span class="token keyword">null</span> <span class="token operator">&amp;&amp;</span>
<span class="token punctuation">(</span><span class="token keyword">typeof</span> obj <span class="token operator">===</span> <span class="token string">'object'</span> <span class="token operator">||</span> <span class="token keyword">typeof</span> obj <span class="token operator">===</span> <span class="token string">'function'</span><span class="token punctuation">)</span> <span class="token operator">&amp;&amp;</span>
<span class="token keyword">typeof</span> obj<span class="token punctuation">.</span>then <span class="token operator">===</span> <span class="token string">'function'</span><span class="token punctuation">;</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token function">isPromiseLike</span><span class="token punctuation">({</span>
then<span class="token punctuation">:</span> <span class="token keyword">function</span><span class="token punctuation">() {</span>
<span class="token keyword">return</span> <span class="token string">''</span><span class="token punctuation">;
}
});</span> <span class="token comment">// true</span>
<span class="token function">isPromiseLike</span><span class="token punctuation">(</span><span class="token keyword">null</span><span class="token punctuation">);</span> <span class="token comment">// false</span>
<span class="token function">isPromiseLike</span><span class="token punctuation">({});</span> <span class="token comment">// false</span>
</pre></div><div class="card code-card"><div class="corner beginner" aria-label="beginner" title="beginner"></div><div class="section card-content"><h4 id="isstring">isString</h4><p>Checks if the given argument is a string. Only works for string primitives.</p><p>Use <code>typeof</code> to check if a value is classified as a string primitive.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">isString</span> <span class="token operator">=</span> val <span class="token operator">=></span> <span class="token keyword">typeof</span> val <span class="token operator">===</span> <span class="token string">'string'</span><span class="token punctuation">;</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token function">isString</span><span class="token punctuation">(</span><span class="token string">'10'</span><span class="token punctuation">);</span> <span class="token comment">// true</span>
</pre></div><div class="card code-card"><div class="corner beginner" aria-label="beginner" title="beginner"></div><div class="section card-content"><h4 id="issymbol">isSymbol</h4><p>Checks if the given argument is a symbol.</p><p>Use <code>typeof</code> to check if a value is classified as a symbol primitive.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">isSymbol</span> <span class="token operator">=</span> val <span class="token operator">=></span> <span class="token keyword">typeof</span> val <span class="token operator">===</span> <span class="token string">'symbol'</span><span class="token punctuation">;</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token function">isSymbol</span><span class="token punctuation">(</span><span class="token function">Symbol</span><span class="token punctuation">(</span><span class="token string">'x'</span><span class="token punctuation">));</span> <span class="token comment">// true</span>
</pre></div><div class="card code-card"><div class="corner beginner" aria-label="beginner" title="beginner"></div><div class="section card-content"><h4 id="isundefined">isUndefined</h4><p>Returns <code>true</code> if the specified value is <code>undefined</code>, <code>false</code> otherwise.</p><p>Use the strict equality operator to check if the value and of <code>val</code> are equal to <code>undefined</code>.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">isUndefined</span> <span class="token operator">=</span> val <span class="token operator">=></span> val <span class="token operator">===</span> undefined<span class="token punctuation">;</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token function">isUndefined</span><span class="token punctuation">(</span>undefined<span class="token punctuation">);</span> <span class="token comment">// true</span>
</pre></div><div class="card code-card"><div class="corner intermediate" aria-label="intermediate" title="intermediate"></div><div class="section card-content"><h4 id="isvalidjson">isValidJSON</h4><p>Checks if the provided string is a valid JSON.</p><p>Use <code>JSON.parse()</code> and a <code>try... catch</code> block to check if the provided string is a valid JSON.</p></div><div class="copy-button-container"><button class="copy-button" aria-label="Copy to clipboard"></button></div><pre class="section card-code language-js"><span class="token keyword">const</span> <span class="token function-variable function">isValidJSON</span> <span class="token operator">=</span> str <span class="token operator">=></span> <span class="token punctuation">{</span>
<span class="token keyword">try</span> <span class="token punctuation">{</span>
<span class="token constant">JSON</span><span class="token punctuation">.</span><span class="token function">parse</span><span class="token punctuation">(</span>str<span class="token punctuation">);</span>
<span class="token keyword">return</span> <span class="token boolean">true</span><span class="token punctuation">;
}</span> <span class="token keyword">catch</span> <span class="token punctuation">(</span><span class="token class-name">e</span><span class="token punctuation">) {</span>
<span class="token keyword">return</span> <span class="token boolean">false</span><span class="token punctuation">;
}
};</span>
</pre><label class="collapse">examples</label><pre class="section card-examples language-js"><span class="token function">isValidJSON</span><span class="token punctuation">(</span><span class="token string">'{"name":"Adam","age":20}'</span><span class="token punctuation">);</span> <span class="token comment">// true</span>
<span class="token function">isValidJSON</span><span class="token punctuation">(</span><span class="token string">'{"name":"Adam",age:"20"}'</span><span class="token punctuation">);</span> <span class="token comment">// false</span>
<span class="token function">isValidJSON</span><span class="token punctuation">(</span><span class="token keyword">null</span><span class="token punctuation">);</span> <span class="token comment">// true</span>
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