tobe a number jest

JavaScript
test('name', () => {
  // array
  expect(Array.isArray(['value'])).toBe(true);
  // string
  expect(typeof 'value').toBe('string');
  // object
  expect({value: 'value'}).toBeTruthy();
  expect(typeof {value: 'value'}).toBe('object');
})
Source

Also in JavaScript: