如何在jest中模拟重载方法？

// example.js
export function sum(a, b) {
  if (typeof a === 'number' && typeof b === 'number') {
    return a + b;
  } else if (typeof a === 'string' && typeof b === 'string') {
    return a.concat(b);
  } else {
    throw new Error('Invalid arguments');
  }
}

// example.test.js
import { sum } from './example';

describe('sum', () => {
  it('should return the sum of two numbers', () => {
    const mockSum = jest.fn().mockImplementation((a, b) => a + b);
    expect(mockSum(2, 3)).toBe(5);
    expect(mockSum).toHaveBeenCalledWith(2, 3);
  });

  it('should concatenate two strings', () => {
    const mockSum = jest.fn().mockImplementation((a, b) => a.concat(b));
    expect(mockSum('Hello', 'World')).toBe('HelloWorld');
    expect(mockSum).toHaveBeenCalledWith('Hello', 'World');
  });

  it('should throw an error for invalid arguments', () => {
    const mockSum = jest.fn().mockImplementation(() => {
      throw new Error('Invalid arguments');
    });
    expect(() => mockSum(2, 'test')).toThrow('Invalid arguments');
    expect(mockSum).toHaveBeenCalledWith(2, 'test');
  });
});