spec.js

const sortby = require('.');

const array = () => [
	{ key: 4 },
	{ key: 3 },
	{ key: 5 },
	{ key: 2 },
];

describe('sortby', () => {
	it('sanity', () => {
		expect(array().sort()).to.deep.equal(array());
	});
	it('Should sort array by a modifier function', () => {
		expect(
			sortby(array(), i => i.key),
		).to.deep.equal(
			[
				{ key: 2 },
				{ key: 3 },
				{ key: 4 },
				{ key: 5 },
			],
		);
	});
	it('Should sort array at a descending order', () => {
		expect(
			sortby(array(), i => i.key, { order: 'desc' }),
		).to.deep.equal(
			[
				{ key: 5 },
				{ key: 4 },
				{ key: 3 },
				{ key: 2 },
			],
		);
	});
	it('Should sort array by a specific key', () => {
		expect(
			sortby(array(), 'key'),
		).to.deep.equal(
			[
				{ key: 2 },
				{ key: 3 },
				{ key: 4 },
				{ key: 5 },
			],
		);
	});
	it('Should sort after using a modifier on the value', () => {
		const array = 			[
			{ key: 'b' },
			{ key: 'A' },
			{ key: 'C' },
		];
		expect(
			sortby(array, 'key'),
		).to.deep.equal(
			[
				{ key: 'A' },
				{ key: 'C' },
				{ key: 'b' },
			],
		);

		expect(
			sortby(array, 'key', { modify: a => a.toLowerCase() }),
		).to.deep.equal(
			[
				{ key: 'A' },
				{ key: 'b' },
				{ key: 'C' },
			],
		);
	});
});