CODEWITHSUNDEEP
typescript
Greg Gum
Greg Gum

Reputation: 37989

How to import an Enum

I have created an enum, but I am having trouble importing and using the enum in VS15.

This is the enum which is contained in enums.ts:

enum EntityStatus {
     New = 0,
     Active = 1,
     Archived = 2,
     Trashed = 3,
     Deleted = 4
}

Visual Studio sees this enum without even importing and so does not give a compile time error. But at runtime, an error is thrown

 Cannot read property 'Archived' of undefined.

So now I try to import it like I import other classes:

 import {EntityStatus} from "../../core/enums";

Visual Studio now gives a compile time error:

 "...enums is not a module ..."

So how do I import the enum?

Upvotes: 117

Views: 138424

Answers (8)

Raviraj Gardi
Raviraj Gardi

Reputation: 298

Short answer

Use .ts extension instead of .d.ts

Explanation:

.d.ts file does not generate the js code on compilation. This means it won't be available at runtime. There is a work around solution which is not always suggested is to define your enums in to .js file but you have to be super careful about the types and you have to do it manually.

Upvotes: -1

Yarco
Yarco

Reputation: 803

Sometimes, you just need to restart the dev server if the grammar is ok.

In my case, I've already defined the export enum .... But the log console still warns me "...has no exported member...", it seems like enum type has a different import mechanism. But after I restarted the dev server, the errors had gone.

Upvotes: 0

Greg Gum
Greg Gum

Reputation: 37989

I was missing the export keyword:

 export enum EntityStatus {
      New = 0,
      Active = 1,
      Archived = 2,
      Trashed = 3,
      Deleted = 4
 }

Then it worked as expected. (But see @Martin Braun's comment below)

Upvotes: 146

luk355
luk355

Reputation: 570

You will get the same Cannot read property 'Foo' of undefined. runtime error when you happen to define your Enum in one of the TypeScript Declaration files (*.d.ts) as these files does not get transpiled into JavaScript.

More details with a sample app can be found here.

Upvotes: 47

Hursh Gupta
Hursh Gupta

Reputation: 35

Encountered similar issue. For me removing the name Enum worked.

Before :

export enum ContentStatusEnum
{
    New = 0,
    Saved = 1,
    Ready = 2,
    Sent = 3,
    Cancel = 4,
    OnError = 5
}

After:

export enum ContentStatus
{
    New = 0,
    Saved = 1,
    Ready = 2,
    Sent = 3,
    Cancel = 4,
    OnError = 5
}

Upvotes: -7

Valerii Sloboda
Valerii Sloboda

Reputation: 128

As @Sachin Kalia said, I had a problem with imports.

I have changed this:

import {MessageAction, MessageDTO} from '../../../generated/dto';

to this:

import {MessageDTO} from '../../../generated/dto';
import {MessageAction} from '../../../generated/dto'

MessageAction is my enum.

Upvotes: 2

Darren Yuhar
Darren Yuhar

Reputation: 373

Just ran across something similar. In my case, I had to ensure the exported enum name was different than the name of the file.

ie.

export enum AccessMode in file access-mode.ts would fail. export enum AccessMode in file access-modes.ts would work.

Upvotes: 23

Sachin Kalia
Sachin Kalia

Reputation: 1107

Kindly try this. It works for me

enums.ts

export enum  Category {Cricket,Tennis,Golf,Badminton}

and in required .ts file import like the way given below:

import {Category} from './enums'

Upvotes: 29

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