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Partial<T>

Constructs a type with all properties of T set to optional.

Since TS 2.1 Spec ↗

Syntax

Partial<Type>

Returns

object type — A new type identical to T but with every property marked optional.

Examples

interface User {
  id: number;
  name: string;
}

function update(user: User, fields: Partial<User>): User {
  return { ...user, ...fields };
}

update({ id: 1, name: 'Ada' }, { name: 'Grace' });

type Config = { host: string; port: number };
const defaults: Partial<Config> = { host: 'localhost' };

Notes

Implemented as a homomorphic mapped type that adds the `?` modifier to every property. It is shallow: nested object properties are not made optional. Use it for patch/update payloads where any subset of fields may be supplied.

See also