如何使用jest模拟typescript中的外部依赖

npm install --save-dev jest ts-jest @types/jest

module.exports = {
  preset: 'ts-jest',
  testEnvironment: 'node',
};

"scripts": {
  "test": "jest"
}

import { fetchData } from './api';

export async function getData() {
  const response = await fetchData();
  return response.data;
}

import { getData } from './example';
import { fetchData } from './api';

jest.mock('./api', () => ({
  fetchData: jest.fn(),
}));

describe('getData', () => {
  it('should return the data from fetchData', async () => {
    const mockData = { data: 'mocked data' };
    (fetchData as jest.MockedFunction<typeof fetchData>).mockResolvedValueOnce(mockData);

    const result = await getData();

    expect(result).toEqual(mockData.data);
    expect(fetchData).toHaveBeenCalledTimes(1);
  });
});

npm test