58 lines
1.6 KiB
Plaintext
58 lines
1.6 KiB
Plaintext
import type {IsEqual} from './is-equal';
|
|
|
|
/**
|
|
Filter out keys from an object.
|
|
|
|
Returns `never` if `Exclude` is strictly equal to `Key`.
|
|
Returns `never` if `Key` extends `Exclude`.
|
|
Returns `Key` otherwise.
|
|
|
|
@example
|
|
```
|
|
type Filtered = Filter<'foo', 'foo'>;
|
|
//=> never
|
|
```
|
|
|
|
@example
|
|
```
|
|
type Filtered = Filter<'bar', string>;
|
|
//=> never
|
|
```
|
|
|
|
@example
|
|
```
|
|
type Filtered = Filter<'bar', 'foo'>;
|
|
//=> 'bar'
|
|
```
|
|
|
|
@see {Except}
|
|
*/
|
|
type Filter<KeyType, ExcludeType> = IsEqual<KeyType, ExcludeType> extends true ? never : (KeyType extends ExcludeType ? never : KeyType);
|
|
|
|
/**
|
|
Create a type from an object type without certain keys.
|
|
|
|
This type is a stricter version of [`Omit`](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-5.html#the-omit-helper-type). The `Omit` type does not restrict the omitted keys to be keys present on the given type, while `Except` 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](https://github.com/microsoft/TypeScript/issues/30825#issuecomment-523668235)).
|
|
|
|
@example
|
|
```
|
|
import type {Except} from 'type-fest';
|
|
|
|
type Foo = {
|
|
a: number;
|
|
b: string;
|
|
c: boolean;
|
|
};
|
|
|
|
type FooWithoutA = Except<Foo, 'a' | 'c'>;
|
|
//=> {b: string};
|
|
```
|
|
|
|
@category Object
|
|
*/
|
|
export type Except<ObjectType, KeysType extends keyof ObjectType> = {
|
|
[KeyType in keyof ObjectType as Filter<KeyType, KeysType>]: ObjectType[KeyType];
|
|
};
|