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FileSystemFlags.exclusive

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 exclusive property on the FileSystemFlags dictionary is used in tandem with the create property to determine whether or not it's acceptable to require that the file not already exist when the reference to it is created by calling FileSystemDirectoryEntry.getFile() or FileSystemDirectoryEntry.getDirectory().

Syntax

fileSystemFlags.exclusive = booleanValue

Values

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 compatibilityUpdate compatibility data on GitHub

	Desktop
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari
Basic support	13 Prefixed 13 Prefixed Prefixed Requires the vendor prefix: webkit	?	50 50 For security reasons, Firefox does not support creating files. This option has no effect.	No	No	No

	Mobile
	Android webview	Chrome for Android	Edge Mobile	Firefox for Android	Opera for Android	iOS Safari	Samsung Internet
Basic support	Yes Prefixed Yes Prefixed Prefixed Requires the vendor prefix: webkit	Yes Prefixed Yes Prefixed Prefixed Requires the vendor prefix: webkit	?	50 50 For security reasons, Firefox does not support creating files. This option has no effect.	No	No	?

FileSystemFlags.exclusive

Syntax

Values

Specifications

Browser compatibilityUpdate compatibility data on GitHub

See also