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.
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 getDirectory
()
returns a FileSystemDirectoryEntry
object corresponding to a directory contained somewhere within the directory subtree rooted at the directory on which it's called.
Syntax
FileSystemDirectoryEntry.getDirectory([path][, options][, successCallback][, errorCallback]);
Parameters
path
Optional- A
USVString
representing an absolute path or a path relative to the directory on which the method is called, describing which directory entry to return. Absolute paths may not be able to be used, for security reasons. options
Optional- An object based on the
FileSystemFlags
dictionary, which allows you to specify whether or not to create the entry if it's missing and if it's an error if the file already exists. These options are currently not useful in Web contexts. successCallback
Optional- A method to be called once the
FileSystemDirectoryEntry
has been created. The method receives a single parameter: theFileSystemDirectoryEntry
object representing the directory in question. errorCallback
Optional- A method to be called if an error occurs. Receives as its sole input parameter a
FileError
object describing the error which occurred.
Return value
Errors
If an error occurs and an errorCallback
was specified, it gets called with a single parameter: a FileError
object describing the error. The {domxref("FileError.code")}} specifies what type of error occurred, as follows:
FileError.NOT_FOUND_ERR
- The
create
option was not specified (or was specified asfalse
), and the directory doesn't exist. FileError.PATH_EXISTS_ERR
- The
create
andexclusive
options were bothtrue
, indicating that the directory should be created but must not already exist, but the directory does in fact already exist. FileError.SECURITY_ERR
- The request to access the directory was denied for security reasons.
FileError.TYPE_MISMATCH_ERR
- The path specified is not a directory; it's probably a file, but might be an unsupported file descriptor such as a pipe; this depends on the user agent to some extent.
FileSystemFlags
The options
parameter is an object which is based on the FileSystemFlags
dictionary; it provides flags which make it possible to adjust the behavior of the getDirectory()
method.
create
Optional- If this property is
true
, and the requested file or directory doesn't exist, the user agent should create it. The default isfalse
. The parent directory must already exist. exclusive
Optional- If
true
, and thecreate
option is alsotrue
, 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 isfalse
.
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.
Example
In this example, a function is presented whose job it is to locate within a user's app data directory a JSON file containing a user dictionary for a specified language, then load that dictionary.
let dictionary = null; function loadDictionaryForLanguage(appDataDirEntry, lang) { dictionary = null; appDataDirEntry.getDirectory("Dictionaries", {}, function(dirEntry) { dirEntry.getFile(lang + "-dict.json", {}, function(fileEntry) { fileEntry.file(function(dictFile)) { let reader = new FileReader(); reader.addEventListener("loadend", function() { dictionary = JSON.parse(reader.result); }); reader.readAsText(dictFile); }); }); }); }
The loadDictionaryForLanguage()
function starts by using getDirectory()
to obtain the FileSystemDirectoryEntry
object representing a subfolder named "Dictionaries" located inside the specified app data directory. The success callback for this takes the resulting directory entry object and calls getFile()
to get a FileSystemFileEntry
object representing the dictionary file; the success callback for this, in turn, creates a new FileReader
and uses it to load the contents of the file. When that is loaded successfully (as indicated by the loadend
event being fired), the loaded text is passed into JSON.parse()
to be reconstituted into a JavaScript object.
Specifications
Specification | Status | Comment |
---|---|---|
File and Directory Entries API The definition of 'getDirectory()' 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) | 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) | No support | No support | No support |