FileReaderSync: FileReaderSync() constructor

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

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

The FileReaderSync() constructor creates a new FileReaderSync.

Syntax

js
new FileReaderSync()

Parameters

None.

Examples

The following code snippet shows creation of a FileReaderSync object using the FileReaderSync() constructor and subsequent usage of the object:

js
function readFile(blob) {
  const reader = new FileReaderSync();
  postMessage(reader.readAsDataURL(blob));
}

Note: This snippet must be used inside a Worker, as synchronous interfaces can't be used on the main thread.

Specifications

Specification
File API
# filereadersyncConstrctr

Browser compatibility

desktop mobile server
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
FileReaderSync() constructor
Chrome – Full support
Chrome 7 (Release date: 2010-10-19)
footnote Full support
Edge – Full support
Edge 12 (Release date: 2015-07-29)
footnote Full support
Firefox – Full support
Firefox 8 (Release date: 2011-11-08)
footnote Full support
Opera – Full support
Opera 12.1 (Release date: 2012-11-20)
footnote Full support
Safari – Full support
Safari 6 (Release date: 2012-07-25)
footnote Full support
Chrome Android – Full support
Chrome Android 18 (Release date: 2012-06-27)
footnote Full support
Firefox for Android – Full support
Firefox for Android 8 (Release date: 2011-11-08)
footnote Full support
Opera Android – Full support
Opera Android 12.1 (Release date: 2012-10-09)
footnote Full support
Safari on iOS – Full support
Safari on iOS 6 (Release date: 2012-09-10)
footnote Full support
Samsung Internet – Full support
Samsung Internet 1 (Release date: 2013-04-27)
footnote Full support
WebView Android – Full support
WebView Android 4.4 (Release date: 2013-12-09)
footnote Full support
WebView on iOS – Full support
WebView on iOS 6 (Release date: 2012-09-10)
footnote Full support
Deno – No support
Deno
footnote No support

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
No support
No support