How to get names of enum entries

Question

I would like to iterate a TypeScript an enum type and get each enumerated symbol name  e g    enum myEnum   entry1  entry2    for  var entry in myEnum            use entry s name here  e g    entry1

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Old question  but  why do not use a const object map   Instead of doing this   enum Foo       BAR   60      EVERYTHING IS TERRIBLE   80    console log Object keys Foo      - gt    60    80    BAR    EVERYTHING IS TERRIBLE   console log Object values Foo      - gt    BAR    EVERYTHING IS TERRIBLE   60  80    Do this  pay attention to the as const cast    const Foo         BAR  60      EVERYTHING IS TERRIBLE  80   as const  console log Object keys Foo      - gt    BAR    EVERYTHING IS TERRIBLE   console log Object values Foo      - gt   60  80

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The only solution that works for me in all cases  even if values are strings  is the following    var enumToString   function enumType  enumValue        for  var enumMember in enumType            if  enumType enumMember   enumValue  return enumMember

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Quite a few answers here and considering I looked it up despite this being 7 years old question  I surmise many more will come here  Here s my solution  which is a bit simpler than other ones  it handles numeric-only text-only mixed value enums  all the same  enum funky       yum   tum  tum   gum    jump   plum   4    const list1   Object keys funky     filter k   gt   Number k  toString       Number NaN toString      console log JSON stringify list1         quot yum quot   quot tum quot   quot gum quot   quot plum quot   quot        for the numeric enum vals  like yum   0  plum   4   typescript adds val   key implicitly  0   yum  4   plum      hence we need to filter out such numeric keys  0 or 4

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For me an easier  practical and direct way to understand what is going on  is that the following enumeration   enum colors   red  green  blue      Will be converted essentially to this   var colors     red  0  green  1  blue  2                  0    red    1    green    2    blue      Because of this  the following will be true   colors red     0 colors colors red       red  colors  red       0   This creates a easy way to get the name of an enumerated as follows   var color  colors   colors red  console log  The color selected is     colors color      It also creates a nice way to convert a string to an enumerated value   var colorName  string    green   var color  colors   colors red  if  colorName in colors  color   colors colorName     The two situations above are far more common situation  because usually you are far more interested in the name of a specific value and serializing values in a generic way

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I hope the question is still relevant  I use such functions  function enumKeys target  Record lt string  number string gt    string       const allKeys  string     Object keys target     const parsedKeys  string            for  const key of allKeys        const needToIgnore  boolean         target target key    toString       key  amp  amp   isNaN parseInt key         if   needToIgnore          parsedKeys push key                return parsedKeys     function enumValues target  Record lt string  number string gt    Array lt string number gt      const keys  string     enumKeys target     const values  Array lt string number gt           for  const key of keys        values push target key           return values     Example  enum HttpStatus     OK    INTERNAL ERROR    FORBIDDEN    FORBIDDEN     NOT FOUND   404    BAD GATEWAY    bad-gateway      console log enumKeys HttpStatus        gt    quot OK quot    quot INTERNAL ERROR quot    quot FORBIDDEN quot    quot NOT FOUND quot    quot BAD GATEWAY quot     console log enumValues HttpStatus        gt   0  1   quot FORBIDDEN quot   404   quot bad-gateway quot

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Another interesting solution found here is using ES6 Map   export enum Type     low    mid    high    export const TypeLabel   new Map lt number  string gt       Type low   Low Season       Type mid   Mid Season       Type high   High Season         USE  console log TypeLabel get Type low       Low Season

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If you only search for the names and iterate later use   Object keys myEnum  map key   gt  myEnum key   filter value   gt  typeof value      string   as string

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I found this question by searching  TypeScript iterate over enum keys   So I just want to post solution which works for me in my case  Maybe it ll help to someone too   My case is the following  I want to iterate over each enum key  then filter some keys  then access some object which has keys as computed values from enum  So this is how I do it without having any TS error       enum MyEnum     ONE    ONE   TWO    TWO        const LABELS             MyEnum ONE    Label one           MyEnum TWO    Label two                 to declare type is important - otherwise TS complains on LABELS type         also  if replace Object values with Object keys -         - TS blames wrong types here   string   is not assignable to MyEnum        const allKeys  Array lt MyEnum gt    Object values MyEnum       const allowedKeys   allKeys filter         type    gt  type     MyEnum ONE            const allowedLabels   allowedKeys map  type    gt           label  LABELS type

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I find that solution more elegant   for  let val in myEnum       if   isNaN  parseInt  val           console log  val        It displays   bar  foo

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Assuming you stick to the rules and only produce enums with numeric values  you can use this code  This correctly handles the case where you have a name that is coincidentally a valid number   enum Color       Red      Green      Blue       10     wat    var names  string         for var n in Color        if typeof Color n       number   names push n     console log names        Red    Green    Blue    10

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I wrote an EnumUtil class which is making a type check by the enum value  export class EnumUtils              Returns the enum keys       param enumObj enum object       param enumType the enum type         static getEnumKeys enumObj  any  enumType  EnumType   any         return EnumUtils getEnumValues enumObj  enumType  map value   gt  enumObj value                    Returns the enum values       param enumObj enum object       param enumType the enum type         static getEnumValues enumObj  any  enumType  EnumType   any         return Object keys enumObj  filter key   gt  typeof enumObj key      enumType          export enum EnumType     Number    number     String    string     How to use it  enum NumberValueEnum    A  0    B  1    enum StringValueEnum    A   A     B   B     EnumUtils getEnumKeys NumberValueEnum  EnumType Number   EnumUtils getEnumValues NumberValueEnum  EnumType Number    EnumUtils getEnumKeys StringValueEnum  EnumType String   EnumUtils getEnumValues StringValueEnum  EnumType String    Result for NumberValueEnum keys    quot A quot    quot B quot   Result for NumberValueEnum values   0  1  Result for StringValueEnumkeys    quot A quot    quot B quot   Result for StringValueEnumvalues    quot A quot    quot B quot

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There are already a lot of answers here but I figure I ll throw my solution onto the stack anyway   TypeScript Playground  enum AccountType     Google    goo     Facebook    boo     Twitter    wit      type Key   keyof typeof AccountType     Google     Facebook     Twitter      this creates a POJO of the enum  reversed  using TypeScript s Record utility const reversed    Object keys AccountType  as Key    reduce  acc  key    gt      acc AccountType key     key   return acc       as Record lt AccountType  string gt     For Clarity         reversed            goo    Google         boo    Facebook         wit    Twitter           reversed AccountType Google       Google         Reference for TypeScript Record  A nice helper function   const getAccountTypeName    type  AccountType    gt      return reversed type         getAccountTypeName AccountType Twitter       Twitter

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According to TypeScript documentation  we can do this via Enum with static functions   Get Enum Name with static functions   enum myEnum        entry1       entry2     namespace myEnum       export function GetmyEnumName m  myEnum          return myEnum m             now we can call it like below myEnum GetmyEnumName myEnum entry1      result entry1    for reading more about Enum with static function follow the below link https   basarat gitbooks io typescript docs enums html

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The best way I think is to just declare the desired enum values  That way accessing them is clean and pretty  every time    enum myEnum   entry1    VALUE1   entry2    VALUE2     for  var entry in myEnum         console log entry       will produce   VALUE1 VALUE2

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If you have enum  enum Diet     KETO    Ketogenic     ATKINS    Atkins     PALEO    Paleo     DGAF    Whatever      Then you can get key and values like   Object keys Diet  forEach  d  Diet    gt      console log d      KETO   console log Diet d      Ketogenic

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It seems that none of the answers here will work with string-enums in strict-mode   Consider enum as   enum AnimalEnum     dog    dog   cat    cat   mouse    mouse      Accessing this with AnimalEnum  dog   may result in an error like   Element implicitly has an  any  type because expression of type  any  can t be used to index type  typeof AnimalEnum  ts 7053    Proper solution for that case  write it as   AnimalEnum  dog  as keyof typeof AnimalEnum

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With current TypeScript Version 1 8 9 I use typed Enums   export enum Option       OPTION1    lt any gt  this is option 1       OPTION2    lt any gt  this is option 2      with results in this Javascript object   Option          OPTION1    this is option 1        OPTION2    this is option 2        this is option 1    OPTION1        this is option 2    OPTION2      so I have to query through keys and values and only return values   let optionNames  Array lt any gt            for  let enumValue in Option        let optionNameLength   optionNames length       if  optionNameLength     0            this optionNames push  enumValue  Option enumValue           else           if  this optionNames optionNameLength - 1  1      enumValue                this optionNames push  enumValue  Option enumValue                         And I receive the option keys in an Array   optionNames      OPTION1    OPTION2

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My Enum is like this   export enum UserSorting       SortByFullName    Sort by FullName        SortByLastname    Sort by Lastame        SortByEmail    Sort by Email        SortByRoleName    Sort by Role        SortByCreatedAt    Sort by Creation date        SortByCreatedBy    Sort by Author        SortByUpdatedAt    Sort by Edit date        SortByUpdatedBy    Sort by Editor        so doing this return undefined   UserSorting UserSorting SortByUpdatedAt    To resolve this issue  I choose another way to do it using a Pipe   import   Pipe  PipeTransform   from   angular core     Pipe       name   enumKey     export class EnumKeyPipe implements PipeTransform      transform value  args  string     null   any       let enumValue   args 0       var keys   Object keys value       var values   Object values value       for  var i   0  i  lt  keys length  i            if  values i     enumValue            return keys i                     return null            And to use it   return this enumKeyPipe transform UserSorting   UserSorting SortByUpdatedAt

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This solution work too   enum ScreenType       Edit   1      New   2      View   4    var type  ScreenType   ScreenType Edit   console log ScreenType type      Edit

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The code you posted will work  it will print out all the members of the enum  including the values of the enum members  For example  the following code  enum myEnum   bar  foo    for  var enumMember in myEnum       console log  quot enum member   quot   enumMember      Will print the following  Enum member  0 Enum member  1 Enum member  bar Enum member  foo  If you instead want only the member names  and not the values  you could do something like this  for  var enumMember in myEnum       var isValueProperty   parseInt enumMember  10   gt   0    if  isValueProperty          console log  quot enum member   quot   myEnum enumMember            That will print out just the names  Enum member  bar   Enum member  foo  Caveat  this slightly relies on an implementation detail  TypeScript compiles enums to a JS object with the enum values being members of the object  If TS decided to implement them different in the future  the above technique could break

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Based on some answers above I came up with this type-safe function signature  export function getStringValuesFromEnum lt T gt  myEnum  T    keyof T        return Object keys myEnum  filter k   gt  typeof  myEnum as any  k       number   as any     Usage  enum myEnum   entry1  entry2    const stringVals   getStringValuesFromEnum myEnum    the type of stringVals is  entry1     entry2  See it in action

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Starting from TypeScript 2 4  the enum would not contain the key as a member anymore  source from TypeScript readme     The caveat is that string-initialized enums can t be reverse-mapped to get the original enum member name  In other words  you can t write Colors  RED   to get the string  Red     My solution   export const getColourKey    value  string     gt        let colourKey           for  const key in ColourEnum            if  value     ColourEnum key                 colourKey   key              break                      return colourKey

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Using a current version TypeScript you can use functions like these to map the Enum to a record of your choosing  Note that you cannot define string values with these functions as they look for keys with a value that is a number   enum STATES     LOGIN    LOGOUT     export const enumToRecordWithKeys    lt E extends any gt  enumeration  E   E   gt      Object keys enumeration       filter key   gt  typeof enumeration key       number        reduce  record  key    gt       record   key   key         as E     export const enumToRecordWithValues    lt E extends any gt  enumeration  E   E   gt      Object keys enumeration       filter key   gt  typeof enumeration key       number        reduce  record  key    gt       record   key   enumeration key          as E     const states   enumToRecordWithKeys STATES  const statesWithIndex   enumToRecordWithValues STATES   console log JSON stringify     STATES    states    statesWithIndex     null  2        Console output       STATES          0    LOGIN        1    LOGOUT        LOGIN   0       LOGOUT   1         states          LOGIN    LOGIN        LOGOUT    LOGOUT          statesWithIndex          LOGIN   0       LOGOUT   1

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In a nutshell if your enums is as below  export enum Colors1     Red   1    Green   2    Blue   3    to get specific  text and value  console log Colors1 Red      1  console log Colors1 Colors1 Red       Red  to get list of value and text  public getTextAndValues e     s  number   string        for  const enumMember in e        if  parseInt enumMember  10   gt   0          console log e enumMember      Value  such as 1 2 3       console log parseInt enumMember  10      Text  such as Red Green Blue             thsi getTextAndValues Colors1   if your enums is as below  export enum Colors2     Red    quot Red quot     Green    quot Green quot     Blue    quot Blue quot     to get specific text and value  console log Colors2 Red      Red console log Colors2  quot Red quot        Red  to get list of value and text  public getTextAndValues e     s  string   string        for  const enumMember in e        console log e enumMember      Value  such as Red Green Blue     console log enumMember       Text  such as Red Green Blue       this getTextAndValues Colors2

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Though the answer is already provided  Almost no one pointed to the docs Here s a snippet enum Enum       A   let nameOfA   Enum Enum A       quot A quot   Keep in mind that string enum members do not get a reverse mapping generated at all

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It is not exactly answer of your question but it is a trick to tackle your problem    export module Gender      export enum Type       Female   1      Male   2         export const List   Object freeze       Type Type Female        Type Type Male             You can extend your list model in a way you want   export const List   Object freeze         name  Type Type Female   value  Type Female           name  Type Type Male   value  Type Male           Now  you can use it in this way   for const gender of Gender List     console log gender name     console log gender value       or   if i     Gender Type Male     console log  I am a man

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Let ts-enum-util  github  npm  do the work for you and provide a lot of additional type-safe utilities  Works with both string and numeric enums  properly ignoring the numeric index reverse lookup entries for numeric enums   String enum   import   enum  from  ts-enum-util    enum Option       OPTION1    this is option 1       OPTION2    this is option 2        type    OPTION1     OPTION2        value    OPTION1    OPTION2   const keys   enum Option  getKeys        type  Option      value    this is option 1    this is option 2   const values    enum Option  getValues      Numeric enum   enum Option       OPTION1      OPTION2       type    OPTION1     OPTION2        value    OPTION1    OPTION2   const keys   enum Option  getKeys        type  Option      value   0  1  const values    enum Option  getValues

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To get the list of the enum values you have to use   enum AnimalEnum     DOG    dog      CAT    cat      MOUSE    mouse     Object values AnimalEnum

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You can use the enum-values package I wrote when I had the same problem   Git  enum-values  var names   EnumValues getNames myEnum

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As of TypeScript 2 4  enums can contain string intializers https   www typescriptlang org docs handbook release-notes typescript-2-4 html  This allows you to write    enum Order         ONE    First         TWO    Second      console log  One is   Order ONE toString         and get this output      One is First

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I wrote a helper function to enumerate an enum   static getEnumValues lt T extends number gt  enumType       T       const values  T           const keys   Object keys enumType     for  const key of keys slice 0  keys length   2         values push  lt T gt  key         return values      Usage   for  const enumValue of getEnumValues lt myEnum gt  myEnum          do the thing     The function returns something that can be easily enumerated  and also casts to the enum type

[enums] How to get names of enum entries?

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