import crypto from 'crypto';

export const getChecksum: (_: PathLike) => Promise<string> = (path: PathLike) =>
  new Promise(resolve => {
    const hash = crypto.createHash('md5');
    const input = fs.createReadStream(path);

    input.on('data', chunk => {
      hash.update(chunk);
    });

    input.on('close', () => {
      resolve(hash.digest('hex'));
    });
  });

Given the function, it can accept a file path, and perform hash.update while streaming the file, I'm trying to write an unit test like below

describe('getChecksum()', () => {
  afterEach(() => {
    vol.reset();
  });

  it('should generate consistent checksum', async () => {
    vol.fromJSON(
      {
        './some/README.md': '1',
        './some/index.js': '2',
      },
      '/app'
    );

    const result = await getChecksum('/app/some/index.js');
    expect(result).toBe('c81e728d9d4c2f636f067f89cc14862c');
  });
});

From the Unit Test above, assertion was able to perform correctly, however, I'm hitting error below

  ● getChecksum() › should generate consistent checksum

    Error [ERR_CRYPTO_HASH_FINALIZED] [ERR_CRYPTO_HASH_FINALIZED]: Digest already called

      63 |
      64 |     input.on('close', () => {
    > 65 |       resolve(hash.digest('hex'));
         |                    ^
      66 |     });
      67 |   });
      68 |

Not too sure which part has gone wrong?