const original = { a: 1, b: 2, c: 3 };
const allowed = ['a', 'b'];
Object.fromEntries(Object.entries(original).filter(
([k, v]) => allowed.includes(k)
));
Object.assign({}, ...allowed.map(k => ({ [k]: original[k] })));
Object.fromEntries(allowed.map(k => [k, original[k]]));