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FileReader: readyState property

The FileReader readyState property provides the current state of the reading operation a FileReader is in. A FileReader exists in one of the following states:

Value State Description
0 EMPTY Reader has been created. None of the read methods called yet.
1 LOADING A read method has been called.
2 DONE The operation is complete.
EMPTY

The FileReader has been created, but no readAs method was called yet.

LOADING

A readAs method was invoked. A File or Blob is being read, and no error has occurred yet.

DONE

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
};

Value

A number which is one of the three possible state constants define for the FileReader API.

Specifications

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
readyState 6 12 3.6 10 11 6 3 18 32 11 6 1.0

See also

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https://developer.mozilla.org/en-US/docs/Web/API/FileReader/readyState