Mock axios.post and capture the request payload

Question

I have

axios.post = jest.fn().mockResolvedValue(< responseData >)

but I need the response data to change depending on what is in the body of the request. How can I capture it, please? Something like

axios.post = jest.fn().< get the body >.mockResolvedValue(< responseData based on the body >)

Answer 1

You are looking for mockImplementation, then you can customize the response data based on request payload.

e.g

import axios from 'axios';

describe('78936100', () => {
  test('should pass', async () => {
    axios.post = jest.fn().mockImplementation((url, data) => {
      if (data.id === 1) {
        return { data: 'a' };
      }
      if (data.id === 2) {
        return { data: 'b' };
      }
    });

    const res1 = await axios.post('http://localhost:8080', { id: 1 });
    expect(res1.data).toEqual('a');

    const res2 = await axios.post('http://localhost:8080', { id: 2 });
    expect(res2.data).toEqual('b');
  });
});