Array includes another array

Watch this recipe in the video Check If An Array Of Strings Includes Another Array.

const countries = ['Germany', 'US', 'Denmark', 'China']
const list = ['China', 'US']
// we want to check if the "countries" array includes
// every country on the given list
list.forEach((country) => {
  expect(countries).to.include(country)
})

We can use lesser known Chai assertions to check if the big list includes all items from the smaller list.

expect(
  countries,
  'all countries are included',
).to.include.members(list)

We can also approach the problem differently. We can compute the difference between the small list and the large list using Lodash _.difference method. If the small list is included in the large list, then the small list should be empty. Otherwise, we get an error with the countries not on the list.

const difference = Cypress._.difference(list, countries)
expect(difference, 'extra countries').to.be.empty