👀 Views: 32 💬 Answers: 1 📅 Created: 2025-06-26

jest axios typescript TypeScript

I'm building a feature where Hey everyone, I'm running into an issue that's driving me crazy... I'm working on a personal project and I’m having trouble mocking an Axios API call in my TypeScript project while writing unit tests with Jest. I have a service that fetches user data from an external API and I want to isolate the tests by mocking the Axios call. Here’s a simplified version of my service: ```typescript import axios from 'axios'; export const userService = { async getUser(userId: string) { const response = await axios.get(`/api/users/${userId}`); return response.data; } }; ``` In my test file, I’m trying to mock the Axios call like this: ```typescript import { userService } from './userService'; import axios from 'axios'; jest.mock('axios'); describe('userService', () => { it('should fetch user data', async () => { const mockResponse = { data: { id: '123', name: 'John Doe' } }; (axios.get as jest.Mock).mockResolvedValue(mockResponse); const user = await userService.getUser('123'); expect(user).toEqual(mockResponse.data); expect(axios.get).toHaveBeenCalledWith('/api/users/123'); }); }); ``` However, when I run the tests, I get the following behavior: ``` TypeError: want to read properties of undefined (reading 'data') ``` I’ve checked that Axios is properly mocked, and I even tried to log the mock implementation, but it doesn’t seem to return anything. I also ensured that my Jest configuration is set up correctly to handle TypeScript. What could I be missing here? Is there a specific setup required for mocking Axios in a TypeScript environment? My dependencies include Jest 27 and Axios 0.21.1. I'm working in a Debian environment. Thanks for any help you can provide! What are your experiences with this?