/**
 * uriToBlob resolves a URI to a Blob object. This is used for
 * React Native to retrieve a file (identified by a file://
 * URI) as a blob.
 */
export function uriToBlob(uri: string): Promise<Blob> {
  return new Promise((resolve, reject) => {
    const xhr = new XMLHttpRequest()
    xhr.responseType = 'blob'
    xhr.onload = () => {
      const blob = xhr.response
      resolve(blob)
    }
    xhr.onerror = (err) => {
      reject(err)
    }
    xhr.open('GET', uri)
    xhr.send()
  })
}