Typeseedcordv0.10.6

Except

Create a type from an object type without certain keys.

We recommend setting the requireExactPropsrequireExactProps option to truetrue.

This type is a stricter version of OmitOmit. The OmitOmit type does not restrict the omitted keys to be keys present on the given type, while ExceptExcept does. The benefits of a stricter type are avoiding typos and allowing the compiler to pick up on rename refactors automatically.

This type was proposed to the TypeScript team, which declined it, saying they prefer that libraries implement stricter versions of the built-in types (microsoft/TypeScript#30825).

type Except<
    ObjectType,
    KeysType extends keyof ObjectType,
    Options extends ExceptOptions = {}
> = _Except<
    ObjectType,
    KeysType,
    ApplyDefaultOptions<ExceptOptions, DefaultExceptOptions, Options>
>;

type Except<
    ObjectType,
    KeysType extends keyof ObjectType,
    Options extends ExceptOptions = {}
> = _Except<
    ObjectType,
    KeysType,
    ApplyDefaultOptions<ExceptOptions, DefaultExceptOptions, Options>
>;

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

type Foo = {
	a: number;
	b: string;
};

type FooWithoutA = Except<Foo, 'a'>;
//=> {b: string}

// @ts-expect-error
const fooWithoutA: FooWithoutA = {a: 1, b: '2'};
// errors: 'a' does not exist in type '{ b: string; }'

type FooWithoutB = Except<Foo, 'b', {requireExactProps: true}>;
//=> {a: number} & Partial<Record<'b', never>>

// @ts-expect-error
const fooWithoutB: FooWithoutB = {a: 1, b: '2'};
// errors at 'b': Type 'string' is not assignable to type 'undefined'.

// The `Omit` utility type doesn't work when omitting specific keys from objects containing index signatures.

// Consider the following example:

type UserData = {
	[metadata: string]: string;
	email: string;
	name: string;
	role: 'admin' | 'user';
};

// `Omit` clearly doesn't behave as expected in this case:
type PostPayload = Omit<UserData, 'email'>;
//=> {[x: string]: string; [x: number]: string}

// In situations like this, `Except` works better.
// It simply removes the `email` key while preserving all the other keys.
type PostPayloadFixed = Except<UserData, 'email'>;
//=> {[x: string]: string; name: string; role: 'admin' | 'user'}

 Object

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

type Foo = {
	a: number;
	b: string;
};

type FooWithoutA = Except<Foo, 'a'>;
//=> {b: string}

// @ts-expect-error
const fooWithoutA: FooWithoutA = {a: 1, b: '2'};
// errors: 'a' does not exist in type '{ b: string; }'

type FooWithoutB = Except<Foo, 'b', {requireExactProps: true}>;
//=> {a: number} & Partial<Record<'b', never>>

// @ts-expect-error
const fooWithoutB: FooWithoutB = {a: 1, b: '2'};
// errors at 'b': Type 'string' is not assignable to type 'undefined'.

// The `Omit` utility type doesn't work when omitting specific keys from objects containing index signatures.

// Consider the following example:

type UserData = {
	[metadata: string]: string;
	email: string;
	name: string;
	role: 'admin' | 'user';
};

// `Omit` clearly doesn't behave as expected in this case:
type PostPayload = Omit<UserData, 'email'>;
//=> {[x: string]: string; [x: number]: string}

// In situations like this, `Except` works better.
// It simply removes the `email` key while preserving all the other keys.
type PostPayloadFixed = Except<UserData, 'email'>;
//=> {[x: string]: string; name: string; role: 'admin' | 'user'}

 Object

ObjectType

ObjectType

ObjectType

KeysType

KeysType extends keyof ObjectType

KeysType extends keyof ObjectType

Options

Options extends ExceptOptions = {}

Options extends ExceptOptions = {}

Except

Create a type from an object type without certain keys.

We recommend setting the requireExactPropsrequireExactProps option to truetrue.

This type was proposed to the TypeScript team, which declined it, saying they prefer that libraries implement stricter versions of the built-in types (microsoft/TypeScript#30825).

type Except< ObjectType, KeysType extends keyof ObjectType, Options extends ExceptOptions = {} > = _Except< ObjectType, KeysType, ApplyDefaultOptions<ExceptOptions, DefaultExceptOptions, Options> >;

import type {Except} from 'type-fest'; type Foo = { a: number; b: string; }; type FooWithoutA = Except<Foo, 'a'>; //=> {b: string} // @ts-expect-error const fooWithoutA: FooWithoutA = {a: 1, b: '2'}; // errors: 'a' does not exist in type '{ b: string; }' type FooWithoutB = Except<Foo, 'b', {requireExactProps: true}>; //=> {a: number} & Partial<Record<'b', never>> // @ts-expect-error const fooWithoutB: FooWithoutB = {a: 1, b: '2'}; // errors at 'b': Type 'string' is not assignable to type 'undefined'. // The `Omit` utility type doesn't work when omitting specific keys from objects containing index signatures. // Consider the following example: type UserData = { [metadata: string]: string; email: string; name: string; role: 'admin' | 'user'; }; // `Omit` clearly doesn't behave as expected in this case: type PostPayload = Omit<UserData, 'email'>; //=> {[x: string]: string; [x: number]: string} // In situations like this, `Except` works better. // It simply removes the `email` key while preserving all the other keys. type PostPayloadFixed = Except<UserData, 'email'>; //=> {[x: string]: string; name: string; role: 'admin' | 'user'} Object