FileReader: readyState property

Available in 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

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

Browser compatibility

See also

• Blob