ts-prime/src/pick.test.ts

A utility library for JavaScript and Typescript.

import { pick } from './pick';
import { pipe } from './pipe';

describe('data first', () => {
    test('it should pick props', () => {
        const result = pick({ a: 1, b: 2, c: 3, d: 4 }, ['a', 'd']);
        expect(result).toEqual({ a: 1, d: 4 });
    });
    test('allow undefined or null', () => {
        expect(pick(undefined as any, ['foo'])).toEqual({});
        expect(pick(null as any, ['foo'])).toEqual({});
    });
    test('support inherited properties', () => {
        class BaseClass {
            testProp() { return 'abc' };
        }
        class TestClass extends BaseClass { }
        const testClass = new TestClass();
        expect(pick(testClass, ['testProp'])).toEqual({ testProp: expect.any(Function) })
    });
});

describe('data last', () => {
    test('it should pick props', () => {
        const result = pipe({ a: 1, b: 2, c: 3, d: 4 }, pick(['a', 'd']));
        expect(result).toEqual({ a: 1, d: 4 });
    });
});