lodash toggle array element

tests.js

import toggleItemInArray from '../toggleItemInArray';

it('toggles item properly', () => {
  expect(toggleItemInArray([], 'a')).toEqual(['a']);
  expect(toggleItemInArray(['a', 'b'], 'a')).toEqual(['b']);
});

toggle.js

/**
 * descructive
 * https://github.com/lodash/lodash/issues/1677
 */
function toggle(collection, item) {
  var idx = _.indexOf(collection, item);
  if(idx !== -1) {
    collection.splice(idx, 1);
  } else {
    collection.push(item);
  }
}

toggleItemInArray.js

// es6 version

import { indexOf, without } from 'lodash';

export default (collection, item) =>
    indexOf(collection, item) !== -1 ? without(collection, item) : [...collection, item];