FileSystemFlags

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 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.

Properties

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`	File/directory condition	Result
`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.

Specifications

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

This API has no official W3C or WHATWG 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
`FileSystemFlags` ExperimentalNon-standard	Chrome Full support 13 Prefixed Full support 13 Prefixed Prefixed Implemented with the vendor prefix: webkit	Edge ?	Firefox Full support 50	IE No support No	Opera No support No	Safari No support No	WebView Android Full support Yes Prefixed Full support Yes Prefixed Prefixed Implemented with the vendor prefix: webkit	Chrome Android Full support Yes Prefixed Full support Yes Prefixed Prefixed Implemented with the vendor prefix: webkit	Firefox Android Full support 50	Opera Android No support No	Safari iOS No support No	Samsung Internet Android ?
`create` ExperimentalNon-standard	Chrome Full support 13 Prefixed Full support 13 Prefixed Prefixed Implemented with the vendor prefix: webkit	Edge ?	Firefox Partial support 50 Notes Partial support 50 Notes Notes For security reasons, Firefox does not support creating files. This option has no effect.	IE No support No	Opera No support No	Safari No support No	WebView Android Full support Yes Prefixed Full support Yes Prefixed Prefixed Implemented with the vendor prefix: webkit	Chrome Android Full support Yes Prefixed Full support Yes Prefixed Prefixed Implemented with the vendor prefix: webkit	Firefox Android Partial support 50 Notes Partial support 50 Notes Notes For security reasons, Firefox does not support creating files. This option has no effect.	Opera Android No support No	Safari iOS No support No	Samsung Internet Android ?
`exclusive` ExperimentalNon-standard	Chrome Full support 13 Prefixed Full support 13 Prefixed Prefixed Implemented with the vendor prefix: webkit	Edge ?	Firefox Partial support 50 Notes Partial support 50 Notes Notes For security reasons, Firefox does not support creating files. This option has no effect.	IE No support No	Opera No support No	Safari No support No	WebView Android Full support Yes Prefixed Full support Yes Prefixed Prefixed Implemented with the vendor prefix: webkit	Chrome Android Full support Yes Prefixed Full support Yes Prefixed Prefixed Implemented with the vendor prefix: webkit	Firefox Android Partial support 50 Notes Partial support 50 Notes Notes For security reasons, Firefox does not support creating files. This option has no effect.	Opera Android No support No	Safari iOS No support No	Samsung Internet Android ?

Legend

Full support: Full support
Partial support: Partial 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.
See implementation notes.: See implementation notes.
Requires a vendor prefix or different name for use.: Requires a vendor prefix or different name for use.