FileReader: readyState property

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 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.

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


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


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.


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

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

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


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


File API
# dom-filereader-readystate

Browser compatibility

BCD tables only load in the browser

See also