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readBlob

Types​

function readBlob<GReadType extends IFileReaderReadType>(
  blob: Blob,
  readType: GReadType
): IObservable<IReadBlobObservableNotifications<GReadType>>
interface IFileReaderFormatsToTypeMap {
  'data-url': string;
  'text': string;
  'array-buffer': ArrayBuffer;
}

type IFileReaderReadType = keyof IFileReaderFormatsToTypeMap;

Definition​

Creates an Observable able to read a Blob.

You may select the output type with IFileReaderFormatsToTypeMap.

The Observable emits values in the form of Notifications:

  • next: the data of the Blob
  • complete: when reading is done
  • error: if an error occurred
  • progress: when reading => IProgress
caution

The FileReader slowly becomes legacy. Instead, you may prefer to use fromReadableStream:

fromReadableStream(blob.stream());

Example​

Read a Blob as an ArrayBuffer​

const blob = new Blob([new Uint8Array([0, 1, 2, 3])]);
const subscribe = readBlob(blob, 'array-buffer');

subscribe((notification) => {
  console.log(notification.name, ':', notification.value);
});

Output:

progress: { loaded: 2, total: 4 }
next: ArrayBuffer([0, 1, 2, 3])
complete