fix: remove unnecessary empty item in case of null-only enum or empty enum (#1022)

[bigen1925]

Status

READY

Description

Remove unnecessary empty item in case of null-only enum or empty enum.

Close #1022

Related PRs

The issue in case of empty enum may exist before.

The issue in case of null-only enum is occured by this PR.

Because null is filtered, null-only enum is handled as empty enum.

branch	PR
alanpoulain:fix/null-enum	link

Todos

• Tests
• Documentation
• Changelog Entry (unreleased)

Steps to Test or Reproduce

Added specification and confirmed generated type files.

[bigen1925]

To avoid that null is quoted like 'null'

[bigen1925]

This code can not handle array enum, or object enum.

output is like

export const ObjectEnum = {
  '[object_Object]': [object Object],
} as const;

I didn't fix because not relevant the issue, but should I leave FIXME comment?

[melloware]

up to you if you want to leave a FIXME but not necessary?

[bigen1925]

@melloware thanks for your review, and sorry for late reply.

I don't think necessary while someone report an issue.

[bigen1925]

I migrated cases in nullable-enum to null-type-v3-0

[bigen1925]

migrated to null-type-v3-0.yaml

[bigen1925]

Before

export type NullOnlyNumberEnum = typeof NullOnlyStringEnum[keyof typeof NullOnlyStringEnum] | null;

// eslint-disable-next-line @typescript-eslint/no-redeclare
export const NullOnlyStringEnum = {
  '': ,
} as const;

export type NullOnlyStringEnum = typeof NullOnlyStringEnum[keyof typeof NullOnlyStringEnum] | null;

// eslint-disable-next-line @typescript-eslint/no-redeclare
export const NullOnlyStringEnum = {
  '': '',
} as const;

export type EmptyEnum = typeof EmptyEnum[keyof typeof EmptyEnum];

// eslint-disable-next-line @typescript-eslint/no-redeclare
export const EmptyEnum = {
  '': '',
} as const;

After

export type NullOnlyNumberEnum = typeof NullOnlyStringEnum[keyof typeof NullOnlyStringEnum] | null;

// eslint-disable-next-line @typescript-eslint/no-redeclare
export const NullOnlyStringEnum = {
} as const;

export type NullOnlyStringEnum = typeof NullOnlyStringEnum[keyof typeof NullOnlyStringEnum] | null;

// eslint-disable-next-line @typescript-eslint/no-redeclare
export const NullOnlyStringEnum = {
} as const;

export type EmptyEnum = typeof EmptyEnum[keyof typeof EmptyEnum];

// eslint-disable-next-line @typescript-eslint/no-redeclare
export const EmptyEnum = {
} as const;

[bigen1925]

Ideally, it is desirable that like this code is generated

export type NullOnlyNumberEnum = null;
export type NullOnlyStringEnum = null;
export type EmptyEnum = never;

, but I think program will get too complex considering combine schema.

Because this is never

const EmptyObject = {} as const
typeof EmptyObject [keyof typeof EmptyObject] // never

, so meaning is the same.