How to include Functions from other files in Node.js

Require() function: It is an inbuilt function and is the easiest way to include functions that exist in separate files. The basic functionality ... 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ChangeLanguage HTMLCSSJavaScriptjQueryPHPBootstrapNodeJSReactJSAngularJSExpressJSTailwindBulmaFoundationReactDesktopjQueryUIjQueryMobileTypeScriptp5.jsTensorflow.jsPrimerCSS RelatedArticles ▲RelatedArticlesInstallationofNode.jsonLinuxHowtoupdateNode.jsandNPMtonextversion?Node.jsfs.readFileSync()MethodHowtoupdateNPM?Node.jsfs.readFile()MethodDifferencebetweenFetchandAxios.jsformakinghttprequestsNode.jsfs.writeFile()MethodHowtoinstallthepreviousversionofnode.jsandnpm?Node.jsforEach()functionExpress.jsres.render()FunctionMongoose|findByIdAndUpdate()FunctionExpress.jsres.sendFile()FunctionDifferencebetweennode.jsrequireandES6importandexportNode.jsfs.readdirSync()MethodLoginformusingNode.jsandMongoDBNode.jsfs.readdir()MethodWhatarethedifferencesbetweennpmandnpx?HowtouseanES6importinNode.js?Express.jsres.redirect()FunctionDifferencebetweenpromiseandasyncawaitinNode.jsNode.jspath.resolve()MethodExpress.jsres.json()FunctionHowtoreadandwriteExcelfileinNode.js?DifferencebetweennpmandyarnExpress.jsres.send()FunctionHowtoreadandwriteJSONfileusingNode.js?Howtoresolve'node'isnotrecognizedasaninternalorexternalcommanderrorafterinstallingNode.js?HowtouseClassinNode.js?Mongoosefind()FunctionHowtoconnectNode.jswithReact.js?InstallationofNode.jsonLinuxHowtoupdateNode.jsandNPMtonextversion?Node.jsfs.readFileSync()MethodHowtoupdateNPM?Node.jsfs.readFile()MethodDifferencebetweenFetchandAxios.jsformakinghttprequestsNode.jsfs.writeFile()MethodHowtoinstallthepreviousversionofnode.jsandnpm?Node.jsforEach()functionExpress.jsres.render()FunctionMongoose|findByIdAndUpdate()FunctionExpress.jsres.sendFile()FunctionDifferencebetweennode.jsrequireandES6importandexportNode.jsfs.readdirSync()MethodLoginformusingNode.jsandMongoDBNode.jsfs.readdir()MethodWhatarethedifferencesbetweennpmandnpx?HowtouseanES6importinNode.js?Express.jsres.redirect()FunctionDifferencebetweenpromiseandasyncawaitinNode.jsNode.jspath.resolve()MethodExpress.jsres.json()FunctionHowtoreadandwriteExcelfileinNode.js?DifferencebetweennpmandyarnExpress.jsres.send()FunctionHowtoreadandwriteJSONfileusingNode.js?Howtoresolve'node'isnotrecognizedasaninternalorexternalcommanderrorafterinstallingNode.js?HowtouseClassinNode.js?Mongoosefind()FunctionHowtoconnectNode.jswithReact.js?HowtoincludeFunctionsfromotherfilesinNode.js?ViewDiscussion ImproveArticle SaveArticle LikeArticle DifficultyLevel: EasyLastUpdated: 29Jun,2020ReadDiscussViewDiscussion ImproveArticle SaveArticle LikeArticle Codereusabilityisanimportantpillarinmoderndayprogramming.CodeReusemeansthepracticeofusinganexistingcodeforanewfunctionorsoftware.Inthisarticle,wewouldlearnhowtousefunctionsfromotherfilesinNode.js. ThisfunctionalitycanbeeasilyimplementedusingtheinbuiltexportandrequirefunctionsofNode.js.Export:Themodule.exportsinNode.jsisusedtoexportanyliteral,functionorobjectasamodule.ItisusedtoincludeJavaScriptfileintoNode.jsapplications.Themoduleissimilartovariablethatisusedtorepresentthecurrentmoduleandexportsisanobjectthatisexposedasamodule.Require()function:Itisaninbuiltfunctionandistheeasiestwaytoincludefunctionsthatexistinseparatefiles.ThebasicfunctionalityofrequireisthatitreadsaJavaScriptfile,executesthefile,andthenproceedstoreturntheexportobject.Letusconsiderthefollowingbasicexample:Filename:cal.jsfunctionsum(x,y){    return(x+y);}  functionsub(x,y){    return(x-y);}  functionmul(x,y){    return(x*y);}  module.exports={add,sub,mul,div};Intheaboveexample,weusethemodule.exportsfunctionsothatwecanuseitinotherfiles.Thefunctionsareenclosedwithincurlybrackets({})accordingtotheformattoexportmultiplefunctionsatatime.Supposewewantedtousethesefunctionsinmain.js,thenitcanbeeasilydoneusingthefollowingcode:Filename:main.js//requiringcal.jsfileconstcal=require("./cal.js")    //Usingthefunctionsfromcal.js constsum=cal.sum(2,2);console.log(sum);   constsub=cal.sub(10,5);console.log(sub);   constproduct=cal.mul(2,3);console.log(product);Thiswillimportthecal.jsfileanditsfunctionsintothemain.jsfile.Runmain.jsfileusingthefollowingcommand:nodemain.jsOutput: 4 5 6 MyPersonalNotes arrow_drop_upSave LikePreviousHowtohidethetableheaderusingJavaScript?Next HowtodefinestyleinformationofadocumentusingHTML5?RecommendedArticlesPage:18,Jun1931,Jul1926,Apr2007,Aug2006,Dec1804,Feb2114,Apr2019,Feb2128,Mar2227,May2231,May2231,Jan2205,Mar2128,Mar1903,May1930,Aug1927,Feb2027,Feb2002,Mar2026,Apr2026,Apr2021,May2031,May2029,Jun20ArticleContributedBy:hiteshkowdiki@hiteshkowdikiVotefordifficultyCurrentdifficulty: EasyEasy Normal Medium Hard ExpertArticleTags:Node.js-MiscNode.jsWebTechnologiesWebtechnologiesQuestionsReportIssueWritingcodeincomment? 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