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()?

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()?

• javascript
• arrays
• reactjs
• jestjs

• 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 Commented Sep 1, 2021 at 14:04

2 Answers 2

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

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));
      });
  });
});