require('fs')

UXP Provides Node.js style file system API, FSAPI. Unlike Entry based File or Folder classes, these methods can directly access a local file or folder with path or file descriptor. The starting point of a path in the native filesystem depends on the scheme. UXP supports plugin-specific storage schemes, such as "plugin:", "plugin-data:", and "plugin-temp:", as well as a native "file:" scheme for the path parameter.
Note:

1. If there are no schemes defined for the path parameter of FSAPI methods, it considers to have "file:" scheme for the path.
   
2. UWP(Universal Windows Platform) has the strict File access permissions, and UXP FSAPI may have access issues with anonymous filepaths. So, XD does not support this feature for compatibility across platforms.
   
3. The native layer of UXP FSAPI is based on libUV except UWP powered features, such as FilePicker and Drag&Drop on Win10 XD.
   

readFile(path, options, callback)

Reads data from the path asynchronously. The file format can be specified with the encoding options. If an encoding is not supplied, the file is assumed to be a binary format.

Returns: Promise<string|ArrayBuffer> - the contents of the file

Example

const data = await fs.readFile("plugin-data:/binaryFile.obj");
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const data = await fs.readFile("plugin-data:/binaryFile.obj");

Example

const text = await fs.readFile("plugin-data:/textFile.txt", {encoding: "utf-8"});
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const text = await fs.readFile("plugin-data:/textFile.txt", {encoding: "utf-8"});

readFileSync(path, options)

Reads data from the path synchronously. The file format can be specified with the encoding options. If an encoding is not supplied, the file is assumed to be a binary format.

Returns: string | ArrayBuffer - the contents of the file

Example

const data = fs.readFileSync("plugin-data:/binaryFile.obj");
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const data = fs.readFileSync("plugin-data:/binaryFile.obj");

Example

const text = fs.readFileSync("plugin-data:/textFile.txt", {encoding: "utf-8"});
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const text = fs.readFileSync("plugin-data:/textFile.txt", {encoding: "utf-8"});

writeFile(path, data, options, callback)

Writes data to the path asynchronously, appending if desired. The format of the file is controlled via the encoding option, and defaults to a binary format.

Returns: Promise<number> - the length of contents written to the file

Example

const bufLen = await fs.writeFile("plugin-data:/binaryFile.obj", new Uint8Array([1, 2, 3]));
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const bufLen = await fs.writeFile("plugin-data:/binaryFile.obj", new Uint8Array([1, 2, 3]));

Example

const strLen = await fs.writeFile("plugin-data:/textFile.txt", "It was a dark and stormy night.\n", {encoding: "utf-8"});
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const strLen = await fs.writeFile("plugin-data:/textFile.txt", "It was a dark and stormy night.\n", {encoding: "utf-8"});

writeFileSync(path, data, options)

Writes data to a path synchronously, appending if desired. The format of the file is controlled via the encoding option, and defaults to a binary format.

Returns: number - the length of contents written to the file

Example

const bufLen = fs.writeFileSync("plugin-data:/binaryFile.obj", new Uint8Array([1, 2, 3]));
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const bufLen = fs.writeFileSync("plugin-data:/binaryFile.obj", new Uint8Array([1, 2, 3]));

Example

const strLen = fs.writeFileSync("plugin-data:/textFile.txt", "It was a dark and stormy night.\n", {encoding: "utf-8"});
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const strLen = fs.writeFileSync("plugin-data:/textFile.txt", "It was a dark and stormy night.\n", {encoding: "utf-8"});

open(path, [flag], [mode], callback)

Opens or a creates a file asynchronously

Returns: Promise<number> - fd(file descriptor)

Example

const fd = await fs.open("plugin-data:/fileToRead.txt", "r");
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const fd = await fs.open("plugin-data:/fileToRead.txt", "r");

close(fd, callback)

Closes a file descriptor asynchronously

Returns: number - 0 if succeeded, otherwise throws an Error

Example

await fs.close(fd);
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await fs.close(fd);

read(fd, buffer, offset, length, position, callback)

Reads data in chunks from the file it refers to the file descriptor

Returns: Promise<Object> - { bytesRead: number, buffer: ArrayBuffer }
Throws:

• Error if invalid file descriptor is passed. if invalid parameter format or value is passed.

Example

const fileSize = 1024;
const buffer = new ArrayBuffer(fileSize);
const fd = await fs.open("plugin-data:/fileToRead.txt", "r");
let bytesReadInTotal = 0;
while (bytesReadInTotal < fileSize) {
    const { bytesRead } = await fs.read(fd, buffer, bytesReadInTotal, 128, -1);
    if (!bytesRead) {
        break;
    }
    bytesReadInTotal += bytesRead;
}
await fs.close(fd);
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1const fileSize = 1024;
2const buffer = new ArrayBuffer(fileSize);
3const fd = await fs.open("plugin-data:/fileToRead.txt", "r");
4let bytesReadInTotal = 0;
5while (bytesReadInTotal < fileSize) {
6    const { bytesRead } = await fs.read(fd, buffer, bytesReadInTotal, 128, -1);
7    if (!bytesRead) {
8        break;
9    }
10    bytesReadInTotal += bytesRead;
11}
12await fs.close(fd);

write(fd, buffer, offset, length, position, callback)

Writes data in chunks to the file it refers to the file descriptor

Returns: Promise<Object> - { bytesWritten, buffer }
Throws:

• Error if invalid file descriptor is passed if invalid parameter format or value is passed

Example

const fd = await fs.open("plugin-data:/fileToWrite.txt", "w+");
const data = "It was a dark and stormy night.\n";
const srcBuffer = new Uint8Array(data.length);
for (let i = 0; i < data.length; i++) {
 srcBuffer[i] = data.charCodeAt(i);
}
const { bytesWritten } = await fs.write(fd, srcBuffer.buffer, 0, srcBuffer.length, 0);
await fs.close(fd);
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1const fd = await fs.open("plugin-data:/fileToWrite.txt", "w+");
2const data = "It was a dark and stormy night.\n";
3const srcBuffer = new Uint8Array(data.length);
4for (let i = 0; i < data.length; i++) {
5 srcBuffer[i] = data.charCodeAt(i);
6}
7const { bytesWritten } = await fs.write(fd, srcBuffer.buffer, 0, srcBuffer.length, 0);
8await fs.close(fd);

lstat(path, callback)

Gets information asynchronously from a file or a folder of the path

Returns: Promise<Object> - see Stats class in Node.js Note: Some methods or properties may not be supportive for the return object due to the platform limitation

Example

const stats = await fs.lstat("plugin-data:/textFile.txt");
const isFile = stats.isFile();
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1const stats = await fs.lstat("plugin-data:/textFile.txt");
2const isFile = stats.isFile();

lstatSync(path)

Gets information synchronously from a file or a folder of the path

Returns: Object - see Stats class in Node.js Note: Some methods or properties may not be supportive for the return object due to the platform limitation

Example

const stats = fs.lstatSync("plugin-data:/textFile.txt");
const birthTime = stats.birthtime;
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1const stats = fs.lstatSync("plugin-data:/textFile.txt");
2const birthTime = stats.birthtime;

rename(oldPath, newPath, callback)

Renames or moves, if required, the file from the oldPath to the newPath

Returns: Promise<number> - 0 if succeeded, otherwise throws an Error

Example

fs.rename("plugin-data:/oldName.txt", "plugin-temp:/newName.txt");
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fs.rename("plugin-data:/oldName.txt", "plugin-temp:/newName.txt");

copyFile(srcPath, destPath, flags, callback)

Copies a file or a folder from the source path to the destination path

Returns: Promise<number> - 0 if succeeded, otherwise throws an Error

Example

const data = fs.copyFile("plugin-data:/copyFrom.txt", "plugin-temp:/copyTo.txt");
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const data = fs.copyFile("plugin-data:/copyFrom.txt", "plugin-temp:/copyTo.txt");

unlink(path, callback)

Deletes a name with the file it refers to asynchronously

Returns: Promise<number> - 0 if succeeded, otherwise throws an Error

Example

await fs.unlink("plugin-data:/fileToDelete.txt");
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await fs.unlink("plugin-data:/fileToDelete.txt");

mkdir(path, options, callback)

Creates a directory of the path asynchronously

Returns: Promise<number> - 0 if succeeded, otherwise throws an Error

Example

await fs.mkdir("plugin-data:/newDir");
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await fs.mkdir("plugin-data:/newDir");

rmdir(path, callback)

Removes a directory asynchronously

Returns: Promise<number> - 0 if succeeded, otherwise throws an Error

Example

await fs.rmdir("plugin-data:/dirToRemove");
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await fs.rmdir("plugin-data:/dirToRemove");

readdir(path, callback)

Reads a directory to list the containing files and directories asynchronously

Returns: Promise<Array<string>> - string array of containing files and directories in the path

Example

const paths = await fs.readdir("plugin-data:/dirToRead");
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const paths = await fs.readdir("plugin-data:/dirToRead");

readdirSync(path)

Reads a directory to list the containing files and directories synchronously

Returns: Array<string> - string array of containing files and directories in the path

Example

const paths = fs.readdirSync("plugin-data:/dirToRead");
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const paths = fs.readdirSync("plugin-data:/dirToRead");