rambdax/_ts-toolbelt/src/Object/IntersectKeys.ts

Extended version of Rambda - a lightweight, faster alternative to Ramda

import {Intersect} from '../Union/Intersect'
import {Match} from '../Any/_Internal'
import {Is} from '../Any/Is'
import {At} from './At'
import {Keys} from './Keys'

/**
@hidden
*/
export type _IntersectMatch<O extends object, O1 extends object, match extends Match> = {
    [K in keyof O]-?: {
        1: K
        0: never
    }[Is<O[K], At<O1, K>, match>]
}[keyof O]

/**
@hidden
*/
type IntersectMatch<O extends object, O1 extends object, match extends Match> =
    O extends unknown
    ? _IntersectMatch<O, O1, match>
    : never

/**
Get the intersecting keys of `O` & `O1`
(If `match = 'default'`, no type checks are done)
@param O to check similarities with
@param O1 to check similarities against
@returns [[Key]]
@example
```ts
```
*/
export type IntersectKeys<O extends object, O1 extends object, match extends Match = 'default'> = {
    'default'     : Intersect<Keys<O>, Keys<O1>>
    'contains->'  : IntersectMatch<O,  O1, 'contains->'>
    'extends->'   : IntersectMatch<O,  O1, 'extends->'>
    '<-contains'  : IntersectMatch<O,  O1, '<-contains'>
    '<-extends'   : IntersectMatch<O,  O1, '<-extends'>
    'equals'      : IntersectMatch<O,  O1, 'equals'>
}[match]