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RequireAtLeastOne type

Create a type that requires at least one of the given keys. The remaining keys are kept as is.

Signature:

export declare type RequireAtLeastOne<
	ObjectType,
	KeysType extends keyof ObjectType = keyof ObjectType,
> = {
    	// For each `Key` in `KeysType` make a mapped type:
    	[Key in KeysType]-?: Required<Pick<ObjectType, Key>> & // 1. Make `Key`'s type required
    		// 2. Make all other keys in `KeysType` optional
    		Partial<Pick<ObjectType, Exclude<KeysType, Key>>>;
}[KeysType] &
	// 3. Add the remaining keys not in `KeysType`
	Except<ObjectType, KeysType>;

Example

``` import {RequireAtLeastOne} from ‘type-fest’;

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

secure?: boolean; };

const responder: RequireAtLeastOne<Responder, ‘text’ | ‘json’> = { json: () => ‘{“message”: “ok”}’, secure: true }; ```

Utilities

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