permutations.js

import test from 'ava';

import {list, range, permutations} from '../../../src/index.js';

test('permutations', (t) => {
	const x = (iterable, repeat, expected) => {
		t.deepEqual(list(permutations(iterable, repeat)), expected);
	};

	x([], 1, []);
	x([], 0, [[]]);
	x([1, 2, 3], 0, [[]]);
	x([1, 2, 3], 4, []);

	x('ABCD', 2, [
		['A', 'B'],
		['A', 'C'],
		['A', 'D'],
		['B', 'A'],
		['B', 'C'],
		['B', 'D'],
		['C', 'A'],
		['C', 'B'],
		['C', 'D'],
		['D', 'A'],
		['D', 'B'],
		['D', 'C'],
	]);

	x(range(0, 3, 1, []), 3, [
		[0, 1, 2],
		[0, 2, 1],
		[1, 0, 2],
		[1, 2, 0],
		[2, 0, 1],
		[2, 1, 0],
	]);
});