It's similar to only or lodash.pick and lodash.pickBy, but written for today's world with TypeScript targeting Object.fromEntries supporting environments:
- https://node.green/#ES2019-features--Object-fromEntries (Node.js >= 12.4)
- https://caniuse.com/#search=fromEntries
- https://polyfill.io/v3/polyfill.min.js?features=Object.getOwnPropertyDescriptors,Object.fromEntries
- core-js polyfilled with Babel
Contrary of all above it also works with arrays and Symbols:
import { pick, pickBy } from 'object-pickby';
it('works with symbols', () => {
expect(
pick({ boo: 'bar', foo: 'eee', [Symbol.for('eee')]: 'aaaa' }, [
'boo',
Symbol.for('eee'),
]),
).toEqual({ boo: 'bar', [Symbol.for('eee')]: 'aaaa' });
});
it('works with array and negative indexes', () => {
expect(pick([1, 2, 3, 4], [1, -2])).toEqual([2, 3]);
});
it('picks items by function, providing accumulated array to predicate', () => {
expect(
pickBy(
[1, 'slon', 2, 'slon', 3, 'foo'],
(val, idx, acc) =>
typeof val === 'string' && idx < 4 && !acc.includes(val),
),
).toEqual(['slon']);
});