FileReader: readyState property

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 available in Web Workers.

The readyState read-only property of the FileReader interface provides the current state of the reading operation. This will be one of the states: EMPTY, LOADING, or DONE.

Value

A number which is one of the three possible state constants defined on the FileReader interface:

FileReader.EMPTY (0)

Reader has been created, but none of the read methods have been called yet.

FileReader.LOADING (1)

A read method has been called. A File or Blob is being read, and no error has occurred yet.

FileReader.DONE (2)

The read operation is complete. This could mean that: the entire File or Blob has been read into memory, a file read error occurred, or abort() was called and the read was cancelled.

Examples

js
const reader = new FileReader();
console.log("EMPTY", reader.readyState); // readyState will be 0

reader.readAsText(blob);
console.log("LOADING", reader.readyState); // readyState will be 1

reader.onloadend = () => {
  console.log("DONE", reader.readyState); // readyState will be 2
};

Specifications

Specification
File API
# dom-filereader-readystate

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
readyState
Chrome – Full support
Chrome 6 (Release date: 2010-09-02)
footnote Full support
Edge – Full support
Edge 12 (Release date: 2015-07-29)
footnote Full support
Firefox – Full support
Firefox 3.6 (Release date: 2010-01-21)
footnote Full support
Opera – Full support
Opera 11 (Release date: 2010-12-16)
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 32 (Release date: 2014-09-02)
footnote Full support
Opera Android – Full support
Opera Android 11 (Release date: 2011-03-22)
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 3 (Release date: 2011-02-22)
footnote Full support
WebView on iOS – Full support
WebView on iOS 6 (Release date: 2012-09-10)
footnote Full support
Deno – Full support
Deno 1.3 (Release date: 2020-08-13)
footnote Full support

Legend

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

Full support
Full support

See also