Type Alias RequireAllOrNone<ObjectType, KeysType>

RequireAllOrNone: (
    Required<Pick<ObjectType, KeysType>>
    | Partial<Record<KeysType, never>>
) & Omit<ObjectType, KeysType>

Create a type that requires all of the given keys or none of the given keys. The remaining keys are kept as is.

Use-cases:

  • Creating interfaces for components with mutually-inclusive keys.

The caveat with RequireAllOrNone is that TypeScript doesn't always know at compile time every key that will exist at runtime. Therefore RequireAllOrNone can't do anything to prevent extra keys it doesn't know about.

Type Parameters

  • ObjectType
  • KeysType extends keyof ObjectType = never

Example

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

type Responder = {
	text?: () => string;
	json?: () => string;
	secure: boolean;
};

const responder1: RequireAllOrNone<Responder, 'text' | 'json'> = {
	secure: true
};

const responder2: RequireAllOrNone<Responder, 'text' | 'json'> = {
	text: () => '{"message": "hi"}',
	json: () => '{"message": "ok"}',
	secure: true
};

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