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

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

/**
@hidden
*/
export type _CompulsoryKeys<O extends object> = {
    [K in keyof O]-?: [O[K] & (undefined | null)] extends [never]
                      ? K
                      : never
}[keyof O]

/**
Get the keys of `O` that are [[Compulsory]]

(⚠️ needs `--strictNullChecks` enabled)
@param O
@returns [[Key]]
@example
```ts
```
*/
export type CompulsoryKeys<O extends object> =
    O extends unknown
    ? _CompulsoryKeys<O>
    : never