import assert from 'assert';
import { slice } from './utils.js';
import differenceBy from '../differenceBy.js';

describe('differenceBy', function() {
  it('should accept an `iteratee`', function() {
    var actual = differenceBy([2.1, 1.2], [2.3, 3.4], Math.floor);
    assert.deepStrictEqual(actual, [1.2]);

    actual = differenceBy([{ 'x': 2 }, { 'x': 1 }], [{ 'x': 1 }], 'x');
    assert.deepStrictEqual(actual, [{ 'x': 2 }]);
  });

  it('should provide correct `iteratee` arguments', function() {
    var args;

    differenceBy([2.1, 1.2], [2.3, 3.4], function() {
      args || (args = slice.call(arguments));
    });

    assert.deepStrictEqual(args, [2.3]);
  });
});