FileSystemFlags

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: 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.

Note that, when create is false, the value of exclusive is irrelevant and ignored.

Option values File/directory condition Result
create exclusive
false n/a 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 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.

Specifications

Specification Status Comment
File and Directory Entries API Draft

See also

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https://developer.mozilla.org/en-US/docs/Web/API/FileSystemFlags