base 64 to blob

toblob.js

export function b64toBlob(data, contentType = '', sliceSize = 512) {
  const byteCharacters = atob(data)
  const byteArrays = []
  for (let offset = 0; offset < byteCharacters.length; offset += sliceSize) {
    const slice = byteCharacters.slice(offset, offset + sliceSize)
    const byteNumbers = new Array(slice.length)
    for (let i = 0; i < slice.length; i++) {
      byteNumbers[i] = slice.charCodeAt(i)
    }
    const byteArray = new Uint8Array(byteNumbers)
    byteArrays.push(byteArray)
  }
  const blob = new Blob(byteArrays, { type: contentType })
  return blob
}