This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

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 FileSystemFlags dictionary defines a set of values which are used when specifying option flags when calling certain methods in the File and Directory Entries API. Methods which accept an options parameter of this type may specify zero or more of these flags as fields in an object, like this:

dataDirectoryEntry.getDirectory("Workspace", { create: true }, function(entry) {

Here, we see that the create property is provided, with a value of true, indicating that the directory should be created if it's not already there.

Note that these option flags currently don't have any useful meaning when used in the scope of Web content, where security precautions prevent the creation of new files or the replacement of existing ones.


create Optional
If this property is true, and the requested file or directory doesn't exist, the user agent should create it. The default is false. The parent directory must already exist.
exclusive Optional
If true, and the create option is also true, the file must not exist prior to issuing the call. Instead, it must be possible for it to be created newly at call time. The default is false.

Values and results

The table below describes the result of each possible combination of these flags depending on whether or not the target file or directory path already exists.

Option values File/directory condition Result
create exclusive
false n/a[1] Path exists and matches the desired type (depending on whether the function called is getFile() or getDirectory() The successCallback is called with a FileSystemFileEntry if getFile() was called or a FileSystemDirectoryEntry if getDirectory() was called.
false n/a[1] Path exists but doesn't match the desired type The errorCallback is called with an appropriate error code (if the callback was provided).
true false Path exists The existing file or directory is removed and replaced with a new one, then the successCallback is called with a FileSystemFileEntry or a FileSystemDirectoryEntry, as appropriate.
true false Path doesn't exist The file or directory is created, then a FileSystemFileEntry or a FileSystemDirectoryEntry is passed to the successCallback, as appropriate.
true true Path exists The errorCallback is called with an appropriate error, such as FileError.PATH_EXISTS_ERR.
true true Path doesn't exist The file or directory is created, then a FileSystemFileEntry or a FileSystemDirectoryEntry is passed to the successCallback, as appropriate.

[1] When create is false, the value of exclusive is irrelevant and ignored.


Specification Status Comment
File and Directory Entries API
The definition of 'FileSystemFlags' in that specification.
Editor's Draft Initial specification.

This API has no official W3C or WHATWG specification.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 13 webkit 50 (50)[1] No support No support No support
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support No support 0.16webkit 50.0 (50)[1] No support No support No support

[1] Firefox does not support creating files for security purposes, so these options are currently ignored.

See also


© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.

API Dictionary File and Directory Entries API File System API Files FileSystemFlags Interface Non-standard Non-Standard Reference