FileReaderSync

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since January 2020.

Note: This feature is only available in Web Workers, except for Service Workers.

The FileReaderSync interface allows to read File or Blob objects synchronously. This interface is only available in workers as it enables synchronous I/O that could potentially block.

Constructor

FileReaderSync()

Returns a new FileReaderSync object.

Instance properties

This interface does not have any properties.

Instance methods

FileReaderSync.readAsArrayBuffer()

This method converts a specified Blob or a File into an ArrayBuffer representing the input data as a binary string.

FileReaderSync.readAsBinaryString()

This method converts a specified Blob or a File into a string representing the input data as a binary string. This method is deprecated, consider using readAsArrayBuffer() instead.

FileReaderSync.readAsText()

This method converts a specified Blob or a File into a string representing the input data as a text string. The optional encoding parameter indicates the encoding to be used (e.g., iso-8859-1 or UTF-8). If not present, the method will apply a detection algorithm for it.

FileReaderSync.readAsDataURL()

This method converts a specified Blob or a File into a string representing the input data as a data URL.

Specifications

Specification
File API
# FileReaderSync

Browser compatibility

BCD tables only load in the browser

See also