Create an enum with string values

Question

Following code can be used to create an enum in TypeScript   enum e       hello   1      world   2      And the values can be accessed by    e hello  e world    How do I create an enum with string values   enum e       hello    hello      error  cannot convert string to e     world    world      error

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With custom transformers  https   github com Microsoft TypeScript pull 13940  which is available in typescript next  you can create enum like object with string values from string literal types   Please look into my npm package  ts-transformer-enumerate   Example usage      The signature of  enumerate  here is  function enumerate lt T extends string gt        K in T   K     import   enumerate   from  ts-transformer-enumerate    type Colors    green     yellow     red   const Colors   enumerate lt Colors gt      console log Colors green       green  console log Colors yellow       yellow  console log Colors red       red

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This works for me   class MyClass       static MyEnum    Value1  Value2  Value3                    Value1   Value1           Value2   Value2           Value3   Value3             or   module MyModule       export var MyEnum    Value1  Value2  Value3                    Value1   Value1           Value2   Value2           Value3   Value3             8   Update  Shortly after posting this I discovered another way  but forgot to post an update  however  someone already did mentioned it above     enum MyEnum       value1    lt any gt  value1         value2    lt any gt  value2         value3    lt any gt  value3

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TypeScript 0 9 0 1  enum e      hello   1      somestr    world      alert e 1          e somestr     TypeScript Playground

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I just declare an interface and use a variable of that type access the enum  Keeping the interface and enum in sync is actually easy  since TypeScript complains if something changes in the enum  like so      error TS2345  Argument of type  typeof EAbFlagEnum  is not assignable   to parameter of type  IAbFlagEnum   Property  Move  is missing in type    typeof EAbFlagEnum     The advantage of this method is no type casting is required in order to use the enum  interface  in various situations  and more types of situations are thus supported  such as the switch case      Declare a TypeScript enum using unique string       per hack mentioned by zjc0816   enum EAbFlagEnum     None         lt any gt   none     Select       lt any gt   sel     Move         lt any gt   mov     Edit         lt any gt   edit     Sort         lt any gt   sort     Clone        lt any gt   clone        Create an interface that shadows the enum      and asserts that members are a type of any  interface IAbFlagEnum       None    any      Select  any      Move    any      Edit    any      Sort    any      Clone   any        Export a variable of type interface that points to the enum  export var AbFlagEnum  IAbFlagEnum   EAbFlagEnum    Using the variable  rather than the enum  produces the desired results   var strVal  string   AbFlagEnum Edit   switch  strVal      case AbFlagEnum Edit      break    case AbFlagEnum Move      break    case AbFlagEnum Clone     Flags were another necessity for me  so I created an NPM module that adds to this example  and includes tests   https   github com djabraham ts-enum-tools

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i was looking for a way to implement descriptions in typescript enums  v2 5  and this pattern worked for me    export enum PriceTypes       Undefined   0      UndefinedDescription    Undefined  as any      UserEntered   1      UserEnteredDescription    User Entered  as any      GeneratedFromTrade   2      GeneratedFromTradeDescription    Generated From Trade  as any      GeneratedFromFreeze   3      GeneratedFromFreezeDescription    Generated Rom Freeze  as any              GetDescription e  any  id  number   string           return e e id  toString      Description              getPriceTypeDescription price  IPricePoint   string           return this GetDescription PriceTypes  price priceType

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TypeScript 2 4  Now has string enums so your code just works    enum E       hello    hello       world    world         TypeScript 1 8  Since TypeScript 1 8 you can use string literal types to provide a reliable and safe experience for named string values  which is partially what enums are used for     type Options    hello     world   var foo  Options  foo    hello      Okay  foo    asdf      Error    More   https   www typescriptlang org docs handbook advanced-types html string-literal-types  Legacy Support  Enums in TypeScript are number based    You can use a class with static members though    class E       static hello    hello       static world    world        You could go plain as well    var E         hello   hello       world   world      Update   Based on the requirement to be able to do something like var test E   E hello  the following satisfies this    class E          boilerplate      constructor public value string                  toString            return this value                values      static hello   new E  hello        static world   new E  world          Sample usage   var first E   E hello  var second E   E world  var third E   E hello   console log  First value is     first   console log first   third

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You can use string enums in the latest TypeScript   enum e       hello    lt any gt  hello       world    lt any gt  world       Source  https   blog rsuter com how-to-implement-an-enum-with-string-values-in-typescript     UPDATE - 2016  A slightly more robust way of making a set of strings that I use for React these days is like this   export class Messages       static CouldNotValidateRequest  string    There was an error validating the request       static PasswordMustNotBeBlank  string    Password must not be blank         import  Messages as msg  from     core messages   console log msg PasswordMustNotBeBlank

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There a lot of answers  but I don t see any complete solutions  The problem with the accepted answer  as well as enum   this  one    is that it disperses the string value you happen to be using through many files  I don t really like the  quot update quot  either  it s complex and doesn t leverage types as well  I think Michael Bromley s answer is most correct  but it s interface is a bit of a hassle and could do with a type  I am using TypeScript 2 0       Here s what I would do export type Greeting    quot hello quot     quot world quot   export const Greeting     hello  Greeting   world  Greeting           hello   quot hello quot       world   quot world quot      Then use like this  let greet  Greeting   Greeting hello  It also has much nicer type   hover-over information when using a helpful IDE  The draw back is you have to write the strings twice  but at least it s only in two places

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Little js-hacky but works  e String e hello

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UPDATE  TypeScript 3 4  You can simply use as const   const AwesomeType        Foo   foo      Bar   bar    as const    TypeScript 2 1  This can also be done this way  Hope it help somebody   const AwesomeType         Foo   foo  as  foo       Bar   bar  as  bar      type AwesomeType    typeof AwesomeType  keyof typeof AwesomeType    console log AwesomeType Bar      returns bar console log AwesomeType Foo      returns foo  function doSth awesometype  AwesomeType        console log awesometype      doSth  foo      return foo doSth  bar      returns bar doSth AwesomeType Bar     returns bar doSth AwesomeType Foo     returns foo doSth  error      does not compile

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TypeScript 2 1    Lookup types  introduced in TypeScript 2 1 allow another pattern for simulating string enums      String enums in TypeScript 2 1 const EntityType         Foo   Foo  as  Foo       Bar   Bar  as  Bar      function doIt entity  keyof typeof EntityType                  EntityType Foo              Foo  doIt EntityType Foo         doIt EntityType Bar         doIt  Foo                   doIt  Bad                      TypeScript 2 4    With version 2 4  TypeScript introduced native support for string enums  so the solution above is not needed  From the TS docs   enum Colors     Red    RED     Green    GREEN     Blue    BLUE

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TypeScript 2 4   You can now assign string values directly to enum members   enum Season       Winter    winter       Spring    spring       Summer    summer       Fall    fall      See  15486 for more information   TypeScript 1 8   In TypeScript 1 8   you can create a string literal type to define the type and an object with the same name for the list of values  It mimics a string enum s expected behaviour   Here s an example   type MyStringEnum    member1     member2    const MyStringEnum         Member1   member1  as MyStringEnum      Member2   member2  as MyStringEnum      Which will work like a string enum      implicit typing example let myVariable   MyStringEnum Member1     ok myVariable    member2                     ok myVariable    some other value            error  desired     explict typing example let myExplicitlyTypedVariable  MyStringEnum  myExplicitlyTypedVariable   MyStringEnum Member1     ok myExplicitlyTypedVariable    member2                 ok myExplicitlyTypedVariable    some other value        error  desired   Make sure to type all the strings in the object  If you don t then in the first example above the variable would not be implicitly typed to MyStringEnum

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to access the enum with its string value you can convert it to object    then you can convert enum to object with proberty    for Example    enum days    one   3   tow    Three     let  days  any   days   if   days one    days one         alert  days one            days 4

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basarat s answer was great  Here is simplified but a little bit extended example you can use   export type TMyEnumType    value1   value2    export class MyEnumType       static VALUE1  TMyEnumType    value1       static VALUE2  TMyEnumType    value2      console log MyEnumType VALUE1       value1   const variable   MyEnumType VALUE2     it has the string value  value2   switch  variable        case MyEnumType VALUE1             code         case MyEnumType VALUE2             code

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Here s a fairly clean solution that allows inheritance  using TypeScript 2 0   I didn t try this on an earlier version   Bonus  the value can be any type   export class Enum lt T gt      public constructor public readonly value  T       public toString         return this value toString           export class PrimaryColor extends Enum lt string gt      public static readonly Red   new Enum   FF0000      public static readonly Green   new Enum   00FF00      public static readonly Blue   new Enum   0000FF       export class Color extends PrimaryColor     public static readonly White   new Enum   FFFFFF      public static readonly Black   new Enum   000000          Usage   console log PrimaryColor Red      Output  Enum   value    FF0000    console log Color Red      inherited     Output  Enum   value    FF0000    console log Color Red value      we have to call  value to get the value     Output   FF0000 console log Color Red toString        toString   works too     Output   FF0000  class Thing     color  Color     let thing  Thing       color  Color Red      switch  thing color      case Color Red           case Color White

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export enum PaymentType                   Cash   1                  Credit   2               var paymentType   PaymentType PaymentType Cash

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In latest version  1 0RC  of TypeScript  you can use enums like this   enum States       New      Active      Disabled        this will show message  0  which is number representation of enum member alert States Active        this will show message  Disabled  as string representation of enum member alert States States Disabled      Update 1  To get number value of enum member from string value  you can use this   var str    Active      this will show message  1  alert States str      Update 2  In latest TypeScript 2 4  there was introduced string enums  like this   enum ActionType       AddUser    ADD USER       DeleteUser    DELETE USER       RenameUser    RENAME USER           Aliases     RemoveUser   DeleteUser      For more info about TypeScript 2 4  read blog on MSDN

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TypeScript  lt  2 4      Utility function to create a K V from a list of strings    function strEnum lt T extends string gt  o  Array lt T gt      K in T   K      return o reduce  res  key    gt        res key    key      return res       Object create null               Sample create a string enum           Create a K V    const Direction   strEnum      North      South      East      West         Create a Type    type Direction   keyof typeof Direction            Sample using a string enum      let sample  Direction   sample   Direction North     Okay sample    North      Okay sample    AnythingElse      ERROR    from https   basarat gitbooks io typescript docs types literal-types html  To the source link you can find more and easier ways to accomplish string literal type

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Faced this issue recently with TypeScript 1 0 1  and solved this way   enum IEvents               A click on a product or product link for one or more products             CLICK              A view of product details             DETAIL              Adding one or more products to a shopping cart             ADD              Remove one or more products from a shopping cart             REMOVE              Initiating the checkout process for one or more products             CHECKOUT              Sending the option value for a given checkout step             CHECKOUT OPTION              The sale of one or more products             PURCHASE              The refund of one or more products             REFUND              A click on an internal promotion             PROMO CLICK    var Events              click            detail            add            remove            checkout            checkout option            purchase            refund            promo click      function stuff event  IEvents  boolean              event can now be only IEvents constants         Events event      event is actually a number that matches the index of the array      stuff  click   won t work  it needs to be called using stuff IEvents CLICK

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Very  very  very simple Enum with string  TypeScript 2 4   import   from     mylib   export enum MESSAGES       ERROR CHART UNKNOWN      ERROR 2    export class Messages       public static get id   MESSAGES           let message              switch  id                case MESSAGES ERROR CHART UNKNOWN                   message    The chart does not exist                   break              case MESSAGES ERROR 2                   message    example                   break                    return message          function log messageName MESSAGES       console log Messages get messageName

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Why not just use the native way of accessing the strings of a enum   enum e     WHY    NOT    USE    NATIVE    e e WHY     this returns string  WHY

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In TypeScript 0 9 0 1  although it occurs a compiler error  the compiler can still compile the ts file into js file  The code works as we expected and Visual Studio 2012 can support for automatic code completion   Update     In syntax  TypeScript doesn t allow us to create an enum with string values  but we can hack the compiler  p  enum Link       LEARN        lt any gt   Tutorial       PLAY         lt any gt   Playground       GET IT       lt any gt    Download       RUN IT       lt any gt   Samples       JOIN IN      lt any gt    Community     alert  Link LEARN                             Link LEARN   alert  Link PLAY                              Link PLAY   alert  Link GET IT                            Link GET IT   alert  Link    Samples        Link            Link   Samples     alert  Link     Community       Link          Link    Community       Playground

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I think you should try with this  in this case the value of the variable won t change and it works quite like enums using like a class also works the only disadvantage is by mistake you can change the value of static variable and that s what we don t want in enums   namespace portal    export namespace storageNames        export const appRegistration    appRegistration       export const accessToken    access token

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I have tried in TypeScript 1 5 like below and it s worked for me  module App Constants      export enum e          Hello    Hello   as any  World    World   as any

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A hacky way to this is  -  CallStatus ts  enum Status       PENDING SCHEDULING      SCHEDULED      CANCELLED      COMPLETED      IN PROGRESS      FAILED      POSTPONED    export   Status   Utils ts  static getEnumString enum any  key any  string       return enum enum key        How to use  Utils getEnumString Status  Status COMPLETED         COMPLETED

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If what you want is mainly easy debug  with fairly type check  and don t need to specify special values for the enum  this is what I m doing   export type Enum      index  number   string    amp     key  string   number     Object          inplace update       export function enum only string lt E extends Enum gt  e  E      Object keys e       filter i   gt  Number isFinite  i        forEach i   gt          const s   e i         e s    s        delete e i              enum AuthType     phone  email  sms  password   enum only string AuthType     If you want to support legacy code data storage  you might keep the numeric keys   This way  you can avoid typing the values twice

[typescript] Create an enum with string values

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