cordova-file-helper

Wrap most of the filesystem operations of Cordova File Plugin into a modern and flexible native Promise API.

API provided by cordova-plugin-file is quite horrible with terrible development experience: callbacks everywhere, need to fetch directories before creating a file, or the need of four operations to truncate and write a to single file. This full Promise-designed API tries to reduce the pain of interacting with the OS in Cordova app.

Getting started

cordova-file-helper needs two other cordova plugins. Install them with Cordova/Phonegap/Ionic CLI according to the needs of you project:

[phonegap] plugin add cordova-plugin-file
[phonegap] plugin add cordova-plugin-device

Warning: This wrapper use native Promise and a big usage of the async/await keywords to improve performance, so your project must target devices that have access to asynchronous functions (see this). If you can't target those devices, you can use cordova-file-helper-legacy plugin, that target those devices.

With npm

npm install cordova-file-helper

Classic CommonJS

const FileHelper = require("cordova-file-helper").FileHelper;

ES6 Import

import { FileHelper } from "cordova-file-helper";

With HTML script

If you don't use Node.js and you can't import libs with require() or import, include FileHelper.js.

<script src="FileHelper.js"></script>

Helper will be available as FileHelper object.

Basics

The File Helper consists in a object that is "related" to a directory, like a terminal.

By default, the object is initialized to the root of application data storage, and you can browse through the storage using cd(), ls(), mv(), cp(), rm(), read and write to files with read() and write() and create directories with mkdir().

Usage

WARNING

This documentation often refer to a path variable. path used with FileHelper are always relative to current working directory. Current working directory can be obtainable with pwd().

Mixed functions

Numerous functions that accept a path parameter accept path as a string or a Entry.

Function that accepts string | Entry as path are:

• write()
• read() and his derivates readJSON(), toInternalURL(), readDataURL()
• mv() and cp(), but only for the dest parameter
• ls()
• tree()

Instanciation

File Helper use cordova.file.externalDataDirectory || cordova.file.dataDirectory as default values for current working directory.

Cordova base-setted directories are available at this page.

// specify a new path in the constructor if you want to skip default values
const helper = new FileHelper(cordova.file.applicationDirectory);

Because FileHelper need that Cordova is ready, you must wait that your FileHelper is ready before you can use it.

await helper.waitInit();

File browsing

exists

Test if a file or directory exists

helper.exists(path); // => Promise<boolean>

isFile

Test if a path exists and is a file

helper.isFile(path); // => Promise<boolean>

isDir

Test if a path exists and is a directory

helper.isDir(path); // => Promise<boolean>

get

Get a FileEntry or a DirectoryEntry. You should not use this method unless you want to manipulate an Entry. get() will fail if file or directory does not exists.

helper.get(path); // => Promise<Entry>

absoluteGet

See get(). You should not use this method unless you want to manipulate an Entry. This method DON'T use a relative path and is not relative to current working directory. absoluteGet() will fail if file or directory does not exists.

You should not use this method !

helper.absoluteGet(path); // => Promise<Entry>

pwd

Get current working directory of the instance. This method do not use Promises !

helper.pwd(); // => string

cd

Change working directory. You can change path relative to current working directory or specify an absolute path (another cordova.file.* for exemple). Promise will be rejected if path does not exists.

/// Change wd to cordova.file.dataDirectory
helper.cd(cordova.file.dataDirectory, /* relative = */ false); // => Promise<void>
 
/// Change wd to parent of actual working directory
helper.cd("..", /* relative = */ true); // => Promise<void>

ls

List existing files into a directory. If path parameter is not specified, list files and directories that are in current working directory.

option_string parameter is a string where you can specify how the function is supposed to work.

• e return EntryObject instead of filenames (see EntryObject information).
• f return only files.
• d return only directories.
• l return FileStats[] objects instead of filenames (string[]).
• p remove subdirectory auto-prefixing, if path is not current working directory. p will not work in recursive mode (r), except if e is enabled.

max_depth parameter specify the maximum number of subdirectories where the function can search in. If max_depth is negative, recursive mode is unlimited. This flag can make function very slow due to the high latency Cordova File System access.

---

EntryObject information

An EntryObject is a classic JS Object that index key=directory_path to value=Entry[].

If your FS is like:

• json
• assets
  • images
    • img.jpg
    • img2.jpg
  • audio
    • sound.mp3

The EntryObject will be organized like:

let o = await helper.ls(undefined /* will list current working directory */, "e", -1);
o = {
    "": /* current working directory */ [ DirectoryEntry<"json">, DirectoryEntry<"assets"> ],
    "json": [],
    "assets": [ DirectoryEntry<"images">, DirectoryEntry<"audio"> ],
    "assets/images": [ FileEntry<"img.jpg">, FileEntry<"img2.jpg"> ],
    "assets/audio": [ FileEntry<"sound.mp3"> ]
};

If you don't activate the r option, your EntryObject will always contains only one key, the empty string (current working directory).

---

Options are combinable into the same string.

helper.ls(); // Promise<string[]>
 
helper.ls(path); // Promise<string[]>
// Warning: If you list a directory that is not cwd, all paths will be prefixed.
// exemple: await helper.ls("assets"); => [ "assets/images", "assets/audio" ]
// To remove prefixing, use "p" parameter
 
helper.ls(path, "ef"); // Promise<EntryObject>
 
helper.ls(path, "l"); // Promise<FileStats[]>

tree

Like ls(path, "pre"), but unflattened. Returns a EntryTree object.

If mime_type parameter is true, file's MIME types will be returns as object values instead of null.

In the same file system of the EntryObject exemple, it gives you:

helper.tree(path, add_mime_types /* = false */); // => Promise<EntryTree>
 
o = await helper.tree();
o = {
    "json": {},
    "assets": {
        "images": {
            "img.jpg": null,
            "img2.jpg": null
        },
        "audio": {
            "sound.mp3": null
        }
    }
};

stats

Get a FileStats object about a file.

helper.stats(path); // => Promise<FileStats>

glob

Find files with a glob pattern.

Specify a glob pattern in the pattern parameter. Specify custom regex flags regex_flags. Accepted flags are all flags supported by RegExp JS object.

helper.glob(pattern, recursive = true, regex_flags = ""); // Promise<string[]>
 
helper.glob("**/*.json", true); // Find all json files below working directory

---

File and directory managment

mv

Move a file or directory to another emplacement. Can also used to rename files/directories.

helper.mv(path, dest = __current_directory__, new_name = __current_name__);
 
// Rename "coucou.txt" file to "hello.txt" and keep it in the same directory
helper.mv("test/folder/coucou.txt", undefined, "hello.txt");
 
// Move "test" to "stats/cookies" folder and name it "test2"
helper.mv("test/", "stats/cookies/", "test2");

cp

Copy a file or directory to another emplacement.

helper.cp(path, dest = __current_directory__, new_name = __current_name__);
 
// Copy "coucou.txt" file to "hello.txt" in the same directory
helper.cp("test/folder/coucou.txt", undefined, "hello.txt");
 
// Copy "test" to "stats/cookies" folder and name the copy "test2"
helper.cp("test/", "stats/cookies/", "test2");

mkdir

Create directory. Automatically create needed parent directories if they does not exists.

// Automatically create cookie, test, second and third
// directories if they doesn't exists
helper.mkdir("cookie/test/second/third");

read

Read a existing file. Read modes are:

• FileHelperReadMode.text (default) : Read as text
• FileHelperReadMode.url : Read as base64 URL
• FileHelperReadMode.array : Read as ArrayBuffer
• FileHelperReadMode.internalURL : Get internal URL of the file
• FileHelperReadMode.json : Read as text and parse to JSON automatically
• FileHelperReadMode.binarystr : Read as binary string
• FileHelperReadMode.fileobj : Return a File object that represent the file

helper.read(path, method); // => Promise<string | any | ArrayBuffer>
 
helper.read("test.txt"); // => Promise<string>
 
// Read a JSON file and parse it automatically
helper.read("forms.json", FileHelperReadMode.json) // => Promise<any>

Sortcuts exists for modes:

helper.readJSON("forms.json"); // => Promise<any>
 
helper.readDataURL("img.jpeg"); // => Promise<string>
 
helper.toInternalURL("test.txt"); // => Promise<string>

readAll

Read all files of a directory using a specific mode.

helper.readAll(directory_path_or_entry, read_mode = FileHelperReadMode.text); // => Promise<string[] | File[] | ArrayBuffer[] | any[]>
 
const forms = await helper.readAll('forms', FileHelperReadMode.json);

write

Write to a file (and create it if it does not exists).

// Empty or create "test.txt", and write "hello, i'm a text string !" to it
helper.write("test.txt", "hello, i'm a text string !");
 
let o = { str: "test" };
// Empty or create "forms.json", and write a JSON.stringified version of o
helper.write("forms.json", o);
 
// Append a string to "test.txt"
helper.write("test.txt", "\nAnd i'm a second one !", true);

touch

Create a file without writing in it.

// Create "text.txt"
helper.touch("test.txt"); // => Promise<FileEntry>

rm

Remove a file or a directory. Parameter r means for recursive. Do NOT use rm with the root directory !

If r is false and the folder contains not-empty folders, remove will fail.

helper.rm(path, r);
 
// Delete test directory and all its content
helper.rm("test/", true);

empty

Clean a directory of all its content. Parameter r means for recursive. If r is false and the folder contains not-empty folders, empty will fail.

helper.empty(path, r);
 
// Clean test directory and remove all its content
helper.empty("test/", true);

---

Helpers

entries

Get entries (files or directories) from numerous paths. If one path does not exists, the function will fail.

helper.entries(...paths); // Promise<Entry[]>
 
helper.entries("test.json", "another_test.txt", "my_dir"); // Promise<[FileEntry, FileEntry, DirectoryEntry]>

entriesOf

Get entries of a directory entry.

helper.entriesOf(dir_entry); // Promise<Entry[]>

newFromCd

Create a new FileHelper instance using current instance as base path. Ensure that the directory exists before creating the instance, then wait that the new instance is ready before returning it.

helper.newFromCd(relative_path); // => Promise<FileHelper>
 
const newHelper = await helper.newFromCd('forms');
 
helper.pwd();// example: cdvfile://localhost/temporary/
newHelper.pwd(); // example: cdvfile://localhost/temporary/forms/

toBlob

Convert almost any JavaScript variable into blob. Automatically encode JavaScript objects with JSON.stringify. Cannot encode JS functions.

helper.toBlob(object);
 
helper.toBlob({ a: "str" }); // => Blob<"{ \"a\": \"str\" }">

readFileAs

If you have a File object, use this to read the object in a specific mode

helper.readFileAs(file, mode); // => Promise<string | ArrayBuffer | any>
 
helper.readFileAs(file, FileHelperReadMode.text); // => Promise<string>

getFile

Extract a File object from a FileEntry or from a path.

helper.getFile(fileEntry); // Promise<File>
 
helper.getFile(path); // Promise<File>

getFileEntryOfDirEntry

Extract a FileEntry object from a DirectoryEntry.

helper.getFileEntryOfDirEntry(dirEntry, filename); // Promise<FileEntry>