Vielzeug

Appearance

intersection ​

Problem ​

You have two arrays and need items that appear in both — for example finding common tags or shared permissions.

Solution ​

Use intersection(source, other, selector?) to return items from source that exist in other.

ts
import { intersection } from '@vielzeug/arsenal';

intersection([1, 2, 3, 4], [2, 4, 6]);
// [2, 4]

const a = [{ id: 1 }, { id: 2 }, { id: 3 }];
const b = [{ id: 2 }, { id: 4 }];
intersection(a, b, (u) => u.id);
// [{ id: 2 }]

Pitfalls ​

  • Without a selector, uses deep equality — use a selector for objects.
  • Result order follows source, not other.