FileReaderSync: readAsArrayBuffer() method

{{APIRef("File API")}} {{AvailableInWorkers("worker_except_service")}}

The readAsArrayBuffer() method of the {{DOMxRef("FileReaderSync")}} interface allows to read {{DOMxRef("File")}} or {{DOMxRef("Blob")}} objects in a synchronous way into an {{jsxref("ArrayBuffer")}}. This interface is only available in workers as it enables synchronous I/O that could potentially block.

Syntax

readAsArrayBuffer(blob)

Parameters

• blob
  • : The {{DOMxRef("File")}} or {{DOMxRef("Blob")}} to read into the {{DOMxRef("File")}} or {{jsxref("ArrayBuffer")}}.

Return value

An {{jsxref("ArrayBuffer")}} representing the file's data.

Exceptions

The following exceptions can be raised by this method:

• NotFoundError {{domxref("DOMException")}}
  • : Thrown if the resource represented by the DOM {{DOMxRef("File")}} or {{DOMxRef("Blob")}} cannot be found, e.g., because it has been erased.
• SecurityError {{domxref("DOMException")}}
  • : Thrown if one of the following problematic situation is detected:
    • the resource has been modified by a third party;
    • too many read are performed simultaneously;
    • the file pointed by the resource is unsafe for a use from the Web (like it is a system file).
• NotReadableError {{domxref("DOMException")}}
  • : Thrown if the resource cannot be read due to a permission problem, like a concurrent lock.
• EncodingError {{domxref("DOMException")}}
  • : Thrown if the resource is a data URL and exceed the limit length defined by each browser.

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• {{DOMxRef("File API", "", "", "nocode")}}
• {{DOMxRef("File")}}
• {{DOMxRef("FileReaderSync")}}
• {{DOMxRef("FileReader")}}
• {{DOMxRef("Blob")}}