Web/API/FileSystemDirectoryEntry/createReader

This is an experimental technologyCheck the Browser compatibility table carefully before using this in production.

The FileSystemDirectoryEntry interface's method createReader() returns a FileSystemDirectoryReader object which can be used to read the entries in the directory.

Syntax

directoryReader = FileSystemDirectoryEntry.createReader();

Parameters

None.

Return value

A FileSystemDirectoryReader object which can be used to read the directory's entries.

Example

This example creates a method called readDirectory(), which fetches all of the entries in the specified FileSystemDirectoryEntry and returns them in an array.

function readDirectory(directory) {
  let dirReader = directory.createReader();
  let entries = [];

  let getEntries = function() {
    dirReader.readEntries(function(results) {
      if (results.length) {
        entries = entries.concat(toArray(results));
        getEntries();
      }
    }, function(error) {
      /* handle error -- error is a FileError object */
    });
  };

  getEntries();
  return entries;
}

This works by creating an internal function, getEntries(), which calls itself recursively to get all the entries in the directory, concatenating each batch to the array. Each iteration, readEntries() is called to get more entries. When it returns an empty array, the end of the directory has beenr reached, and the recursion ends. Once control is returned to readDirectory(), the array is returned to the caller.

Specifications

Specification	Status	Comment
File and Directory Entries APIThe definition of 'createReader()' in that specification.	Draft	Initial specification.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`createReader` Experimental'	Chrome Full support 13	Edge Full support 79	Firefox Full support 50	IE No support No	Opera No support No	Safari Full support 11.1	WebView Android Full support ≤37	Chrome Android Full support 18	Firefox Android Full support 50	Opera Android No support No	Safari iOS Full support 11.3	Samsung Internet Android Full support 1.0

Legend

Full support: Full support
No support: No support
Experimental. Expect behavior to change in the future.': Experimental. Expect behavior to change in the future.