Expected Array but received array in Jest

Question

I created unit (async) test in Jest. But when I get response from server:

[
    {
        name: "My name"
    },
    {
        name: "Another name"
    }
]

and test it:

test('Response from server', () => {
    get('my-url').end(error, response) => {
        expect(response.body).toBe(expect.any(Array))
    }
})

some error occurs:

Comparing two different types of values. Expected Array but received array.

It's working when I use expect(response.body).any(Array). But is there any fix for expect.toBe()?

expect(response.body).any(Array) shouldn't work. .any doesn't exist on the response from expect() but on expect itself. The referenced code gives this error: "TypeError: expect(...).any is not a function". — Samuel Neff
– Samuel Neff, Commented Sep 1, 2021 at 14:04

Alexander Elgin · Accepted Answer · 2019-01-31 07:08:58Z

16

You should use toEqual (not toBe) to compare objects and arrays. Use toBe for scalar data types only. If you like to check the response data type use typeof operator

edited Jan 31, 2019 at 7:08

answered Sep 16, 2017 at 16:28

Alexander Elgin

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Comments

Skyes Crawford · Accepted Answer · 2024-02-26 02:56:32Z

1

I found the answer above is really helpful, this how I implement it in my test

describe("GET /api/books", () => {
  it("should get all books", () => {
    return request(app)
      .get("/api/books")
      .expect(200)
      .expect("Content-Type", /json/)
      .then((res) => {
        expect(res.body).toEqual(expect.any(Array));
      });
  });
});

answered Feb 26, 2024 at 2:56

Skyes Crawford

111 bronze badge

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