FileSystemDirectoryEntry.createReader()

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

Non-standard
This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

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 API
The definition of 'createDirectory()' in that specification.
Draft Initial specification.

This API has no official W3C or WHATWG specification.

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung Internet
Basic support
ExperimentalDeprecatedNon-standard
Chrome Full support 13Edge No support NoFirefox Full support 50IE No support NoOpera No support NoSafari No support NoWebView Android Full support YesChrome Android Full support YesEdge Mobile ? Firefox Android Full support 50Opera Android No support NoSafari iOS No support NoSamsung Internet Android ?

Legend

Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
Non-standard. Expect poor cross-browser support.
Non-standard. Expect poor cross-browser support.
Deprecated. Not for use in new websites.
Deprecated. Not for use in new websites.

See also

Document Tags and Contributors

Contributors to this page: fscholz, Sheppy
Last updated by: fscholz,