JavaScript Tutorial => Getters and Setters

In a class definition, a getter is written like a no-argument method prefixed by the get keyword. A setter is similar, except that it accepts one argument (the ... 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Inaclassdefinition,agetteriswrittenlikeano-argumentmethodprefixedbythegetkeyword.Asetterissimilar,exceptthatitacceptsoneargument(thenewvaluebeingassigned)andthesetkeywordisusedinstead. Here'sanexampleclasswhichprovidesagetterandsetterforits.nameproperty.Eachtimeit'sassigned,we'llrecordthenewnameinaninternal.names_array.Eachtimeit'saccessed,we'llreturnthelatestname. classMyClass{ constructor(){ this.names_=[]; } setname(value){ this.names_.push(value); } getname(){ returnthis.names_[this.names_.length-1]; } } constmyClassInstance=newMyClass(); myClassInstance.name='Joe'; myClassInstance.name='Bob'; console.log(myClassInstance.name);//logs:"Bob" console.log(myClassInstance.names_);//logs:["Joe","Bob"] Ifyouonlydefineasetter,attemptingtoaccessthepropertywillalwaysreturnundefined. constclassInstance=newclass{ setprop(value){ console.log('setting',value); } }; classInstance.prop=10;//logs:"setting",10 console.log(classInstance.prop);//logs:undefined Ifyouonlydefineagetter,attemptingtoassignthepropertywillhavenoeffect. constclassInstance=newclass{ getprop(){ return5; } }; classInstance.prop=10; console.log(classInstance.prop);//logs:5 PDF-DownloadJavaScriptforfree Previous Next ThismodifiedtextisanextractoftheoriginalStackOverflowDocumentationcreatedbyfollowingcontributorsandreleasedunderCCBY-SA3.0 ThiswebsiteisnotaffiliatedwithStackOverflow SUPPORT&PARTNERS Advertisewithus Contactus PrivacyPolicy STAYCONNECTED Getmonthlyupdatesaboutnewarticles,cheatsheets,andtricks.  Subscribe