How to make Typescript enum with implements interfaces

i current has this 2 enum

all enum ENNAME keys should only include of enum POSTAG keys

export enum POSTAG
{
    BAD = 0x80000000,
    D_A = 0x40000000,
    D_B = 0x20000000,
    D_C = 0x10000000,
}

export enum ENNAME
{
    D_A = 'a',
    D_B = 'b',
    D_C = 'c',
}

---

is there has any way make something like this??

export interface ENNAME
{
    [k: keyof POSTAG]: string,
}

How to make Typescript enum with implements interfaces

i current has this 2 enum

all enum ENNAME keys should only include of enum POSTAG keys

export enum POSTAG
{
    BAD = 0x80000000,
    D_A = 0x40000000,
    D_B = 0x20000000,
    D_C = 0x10000000,
}

export enum ENNAME
{
    D_A = 'a',
    D_B = 'b',
    D_C = 'c',
}

---

is there has any way make something like this??

export interface ENNAME
{
    [k: keyof POSTAG]: string,
}

• javascript
• node.js
• typescript
• types
• enums

Share Improve this question Follow asked Jan 8, 2019 at 18:59 blueloversbluelovers 1,26522 gold badges1212 silver badges2525 bronze badges

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1 Answer 1

Sorted by: Reset to default 4

You can't make an enum extend an interface. The best you can do is set up some pile-time checking of the types to produce a warning if you make a mistake, such as:

interface ENNAMEInterface extends Record<Exclude<keyof typeof POSTAG, "BAD">, string> { }
type VerifyExtends<T, U extends T> = true
type VerifyENNAME = VerifyExtends<ENNAMEInterface, typeof ENNAME>; // okay

That should pile if the value ENNAME has the same keys as the value POSTAG (minus "BAD") with string values. Otherwise, VerifyENNAME will give you an error:

export enum ENNAME {
  D_A = 'a',
  D_B = 'b',
  // oops, D_C is missing 
}

type VerifyENNAME = VerifyExtends<ENNAMEInterface, typeof ENNAME>; // error
//                                                 ~~~~~~~~~~~~~
//  Property 'D_C' is missing in type 'typeof ENNAME' but required in type 'ENNAMEInterface'.

Hope that helps. Good luck!