SetOptional

Makes the given keys of an object optional, leaving the rest unchanged. Like the built-in Partial, but scoped to specific keys.

type Draft = SetOptional<T, K>;

Usage

SetOptional<T, K>

Use it when only part of an object may be missing, such as a draft that is still being filled in.

import type { SetOptional } from 'es-toolkit/types';

interface Account {
  accountId: string;
  productCode: string;
  nickname: string;
}

// A nickname may not be filled in yet.
type AccountDraft = SetOptional<Account, 'nickname'>;
// => { accountId: string; productCode: string; nickname?: string }

const draft: AccountDraft = { accountId: 'a_1', productCode: 'SAVINGS' };

// Several keys at once.
type PartiallyFilled = SetOptional<Account, 'nickname' | 'productCode'>;

Type Parameters

• T: The object type to transform.
• K: The keys to make optional. Must be keys of T.
• It distributes over unions, so a union stays a union and each member keeps its own shape.