🎁 Pull Request

• Used a clear / meaningful title for this pull request
• Tested the changes in your own code (on your projects)
• Added / Edited tests to reflect changes (tst folder)
• Have read the Contributing part of the Readme
• Passed npm test

Fixes

Having a non-object in a union as a property breaks O.P.Pick for any properties in the union.

For example, note how PartOneAndTwo incorrectly picks the nested object:

// {a: 'a'}
type PartOne = O.P.Pick<{a: 'a', b: 'b'}, ['a', 'b']>;
// {a: {b: 'ab'}}
type PartTwo = O.P.Pick<{a: {b: 'ab', c: 'ac'}, b: 'b'}, ['a', 'b']>;
// {a: 'a' | {b: 'ab', c: 'ac'}}
type PartOneAndTwo = O.P.Pick<{a: {b: 'ab', c: 'ac'} | 'a', b: 'b'}, ['a', 'b']>;

This PR fixes PartOneAndTwo to evaluate to {a: 'a' | {b: 'ab'}}.

Why have you made changes?

To fix the issues above.

What changes have you made?

• Added an infer to O.P.Pick, making the conditional type distributive. This removes the need to cast Picked[K] to an object and distributes Picked[K] over all types.

What tests have you updated?

• added a new test for O.P.Pick in tst/Object.ts

Is there any breaking changes?

• Yes, I changed the public API & documented it
• Yes, I changed existing tests
• No, I added to the public API & documented it
• No, I added to the existing tests
• I don't know

Anything else worth mentioning?

Working with advanced types in TypeScript is really fun 😁