describe('IOEither chain', () => {
  it('extracts name from valid JSON', () => {
    const result = extractName('{"name":"Alice","age":30}')()
    expect(E.isRight(result)).toBe(true)
    if (E.isRight(result)) {
      expect(result.right).toBe('Alice')
    }
  })

  it('fails on invalid JSON', () => {
    const result = extractName('{invalid}')()
    expect(E.isLeft(result)).toBe(true)
  })

  it('fails when name is missing', () => {
    const result = extractName('{"age":30}')()
    expect(E.isLeft(result)).toBe(true)
  })
})