UndefinedOnPartialDeep (opposite of PartialOnUndefinedDeep)

[kachkaev]

It’d be great have a type similar to PartialOnUndefinedDeep, which does the opposite:

import type { UndefinedOnPartialDeep } from 'type-fest';

interface Settings {
  optionA: string;
  optionB?: number;
  subOption: {
    subOptionA: boolean;
    subOptionB?: boolean;
  };
}

const testSettingsA: Settings = {
  optionA: 'foo',
  optionB: undefined, // TS error if exactOptionalPropertyTypes is true
  subOption: {
    subOptionA: true,
    subOptionB: undefined, // TS error if exactOptionalPropertyTypes is true
  },
};

const testSettingsB: UndefinedOnPartialDeep<Settings> = {
  optionA: 'foo',
  optionB: undefined, // 👉 optionB can be set to undefined now
  subOption: {
    subOptionA: true,
    subOptionB: undefined, // 👉 subOptionB can be set to undefined now
  },
};

See #426 and exactOptionalPropertyTypes docs for context.