jest test array code example

Example 1: jest test array of objects

const users = [{id: 1, name: 'Hugo'}, {id: 2, name: 'Francesco'}];

test('we should have ids 1 and 2', () => {
  expect(users).toEqual(
    expect.arrayContaining([
      expect.objectContaining({id: 1}),
      expect.objectContaining({id: 2})
    ])
  );
});

Example 2: jest check array of string

const fruits = ['apple', 'cat'];

test('should have array of string', () => {
  expect(fruits).toEqual(
    expect.arrayContaining([expect.any(String)])
  );
});

Example 3: Jest toContain

# 1. Use '.toContain' when you want to check that an item is in an array.
# 2 '.toContain' can also check whether a string is a substring of another string.
test('the flavor list contains lime', () => {
  expect(['lime', 'mangle']).toContain('lime');
});

test('the flavor list contains lime', () => {
  expect("lime juice").toContain('lime');
});