jest expect add \\ in string code example
Example 1: jest expect not contain
expect('some string').toEqual(expect.not.stringContaining('something else'))
Example 2: expect any function jest
expect(something).toEqual(expect.any(Function))
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');
});