Cannot read property 'descriptor' of undefined #4

function loadLabeledImages() {
  const labels = ['Black Widow', 'Captain America', 'Captain Marvel', 'Hawkeye', 'Jim Rhodes', 'Thor', 'Tony Stark','Bhaiya']
  return Promise.all(
    labels.map(async label => {
      const descriptions = []
      for (let i = 1; i <= 2; i++) {
        const img = await faceapi.fetchImage(`labeled_images/${label}/${i}.jpg`)
        const detections = await faceapi.detectSingleFace(img).withFaceLandmarks().withFaceDescriptor()
        descriptions.push(detections.descriptor)
      }

      return new faceapi.LabeledFaceDescriptors(label, descriptions)
    })
  )
}