Possible optional chaining gains?

opt.ts

// Without optional chaining.

export const getInstance = async (instanceId: string): Promise<Instance> => {
  const result = await ec2Client
    .describeInstances({ InstanceIds: [instanceId] })
    .promise()
  if (!result.Reservations) {
    throw new Error(`Could not find instance ${instanceId}`)
  }
  if (result.Reservations.length > 1) {
    throw new Error('Found more than one reservation.')
  }
  const r = result.Reservations[0]
  if (!r.Instances) {
    throw new Error('Reservation contained no instances.')
  }
  if (r.Instances.length > 1) {
    throw new Error('Found more than one instance.')
  }
  return r.Instances[0]
}

// With optional chaining?

export const getInstance = async (instanceId: string): Promise<Instance> => {
  const result = await ec2Client
    .describeInstances({ InstanceIds: [instanceId] })
    .promise()
  const instance = result.Reservations?.[0]?.Instances?.[0]?
  if (!instance) {
    throw new Error(`Could not find instance ${instanceId}`)
  }
  return instance
}