Enums cannot be used as a value when imports using the import type declaration.

[AnmSaiful]

Bug Report

🕗 Version Information

TypeScript v4.1.3 Node.js v10.23.1 linux/amd64

⏯ REPL Link

https://replit.com/@AnmSaiful/ts-import-type-enum

💻 Code

// ---- enums.ts ----
export enum Sex {

  Male    = "male",
  Female  = "female",

}

// ---- type.ts ----
export * as Enum from "./enums";

// ---- index.ts ----
import type { Enum } from "./type";

function enumTest(): Enum.Sex {

  return Enum.Sex.Male;

}

console.log( enumTest() );

🙁 Actual behavior

It does not allow using Enum from the composed imported type and says:

'Enum' cannot be used as a value because it was imported using 'import type'.

🙂 Expected behavior

It should allow using Enums from the imported type.

[DanielRosenwasser]

import type doesn't generate any code, so you'll get a runtime error when evaluating Enum.Sex because Enum won't refer to anything in the output JavaScript.

[AnmSaiful]

@DanielRosenwasser I'm using import type to avoid failing ESLint's no-cycle rule because my type imports result from circular dependency. It is normal because the type definition file uses the class file (for the instance type), and class file uses the type definition file.

I can suppress the ESLint error for that line, but should this be practiced?

[AnmSaiful]

Perhaps we should move this to the feature list instead of bug?

[DanielRosenwasser]

import type is meant to be erased away entirely - so unfortunately there's no way to make this functionality work that isn't at odds with design decisions we're already set on. At best, there's the discussion of whether we'd want to make exceptions for const enums, which is awaiting more feedback at #40344.

[AnmSaiful]

Currently, I'm using plain objects as const along with typeof Obj[ keyof typeof Obj] as a workaround. Hopefully, TS will solve the enum issue soon.