File System

The File System module provides high-level abstractions for file system entities such as files, folders, known folders, paths, separators, etc.

Usage

import { knownFolders, path, File, Folder } from "tns-core-modules/file-system";

File Usage

Create folders, files and file content

let documents = knownFolders.documents();
this.folder = documents.getFolder(this.folderName || "testFolder");
this.file = this.folder.getFile((this.fileName || "testFile") + ".txt");

this.file.writeText(this.fileTextContent || "some random content")
    .then(result => {
        this.file.readText()
            .then(res => {
                this.successMessage = "Successfully saved in " + this.file.path;
                this.writtenContent = res;
                this.isItemVisible = true;
            });
    }).catch(err => {
        console.log(err);
    });

Removing a File

this.file.remove()
    .then(res => {
        // Success removing the file.
        this.resultMessage = "File successfully deleted!";
    }).catch(err => {
        console.log(err.stack);
    });

Normalize a Path

let documentsFolder = knownFolders.documents();
let currentAppFolder = knownFolders.currentApp();
let tempFolder = knownFolders.temp();

let testPath = "///test.txt";
// Get a normalized path such as <folder.path>/test.txt from <folder.path>///test.txt
this.documents = path.normalize(documentsFolder.path + testPath);
this.currentApp = path.normalize(currentAppFolder.path + testPath);
this.temp = path.normalize(tempFolder.path + testPath);

Path Join

// Generate a path like <documents.path>/myFiles/test.txt
documentsFolder = knownFolders.documents();
let filePath = path.join(documentsFolder.path, "myFiles", "test.txt");

Get the Path Separator

// An OS dependent path separator, "\" or "/".
let separator = path.separator;

Get or Create a File With Path

let documentsFolder = knownFolders.documents();
let myPath = path.join(documentsFolder.path, "FileFromPath.txt");
let file = File.fromPath(myPath);

// Writing text to the file.
file.writeText(this.textContentToBeSaved)
    .then(result => {
        // Succeeded writing to the file.
        file.readText().then(res => {
            // Succeeded read from file.
            this.isContentSaved = true;
            this.savedContent = res;
            console.log("File content: " + res);
        });
    }).catch(err => {
        console.log(err.stack);
    });

Reading from a File

this.file.readText()
    .then(res => {
        this.writtenContent = res;
    }).catch(err => {
        console.log(err.stack);
    });

Reading binary data from a File

let image = imageSource.fromResource("icon");
let folder = knownFolders.documents();
let myPath = path.join(folder.path, "Test.png");
let saved = image.saveToFile(myPath, "png");

if (saved) {
    this.imageFile = File.fromPath(myPath);
    this.binarySource = this.imageFile.readSync(err => { console.log("Error:" + err); });
    console.log(this.binarySource);

Writing binary data to a File

this.imageFile.writeSync(this.binarySource, err => {
    console.log(err);
});

Checking if a File Exists

this.documents = knownFolders.documents();
let myPath = path.join(this.documents.path, "Text.txt");
let exists = File.exists(myPath);
console.log("Does Text.txt exists: " + exists);

Renaming a File

this.file.rename(this.fileName + ".txt")
    .then(res => {
        // File Successfully Renamed.
        this.fileSuccessMessage = "File renamed to: " + this.fileName + ".txt";
        this.isItemVisible = true;
    }).catch(err => {
        // Error!
    });

Folder Usage

Create folders, files and file content

let documents = knownFolders.documents();
this.folder = documents.getFolder(this.folderName || "testFolder");
this.file = this.folder.getFile((this.fileName || "testFile") + ".txt");

this.file.writeText(this.fileTextContent || "some random content")
    .then(result => {
        this.file.readText()
            .then(res => {
                this.successMessage = "Successfully saved in " + this.file.path;
                this.writtenContent = res;
                this.isItemVisible = true;
            });
    }).catch(err => {
        console.log(err);
    });

Removing a Folder

// Remove a folder and recursively its content.
this.myFolder.remove()
    .then(fres => {
        // Success removing the folder.
        this.resultMessage = "Folder successfully deleted!";
    }).catch(err => {
        console.log(err.stack);
    });

Clearing the Contents of a Folder

this.myFolder.clear()
    .then(res =>  {
        // Successfully cleared the folder.
        this.resultMessage = "Folder successfully cleared!";
    }).catch(err => {
        console.log(err.stack);
    });

Get or Create a Folder With Path

let folderPath = path.join(knownFolders.documents().path, "music");
let folder = Folder.fromPath(folderPath);

Getting Folder Contents

Getting all folder entities in array may be slow with large number of files. Enumerating the folder entities would iterate the files one by one without blocking the UI.

this.documents = knownFolders.documents();
this.documents.getEntities()
    .then(entities => {
        // entities is array with the document's files and folders.
        entities.forEach(entity => {
            // console.log(entity.name);
            // console.log(entity.path);
            // console.log(entity.lastModified);
            this.folderEntities.push(
                new FolderEntity(entity.name, entity.path, entity.lastModified.toString())
            );
        });
    }).catch(err => {
        // Failed to obtain folder's contents.
        console.log(err.stack);
    });

Checking if a Folder Exists

let temp = knownFolders.temp();
let tempExists = Folder.exists(temp.path);
console.log("Does temp folder exists: " + tempExists);

Renaming a Folder

this.myFolder.rename(this.folderName)
    .then(res => {
        // Folder Successfully Renamed.
        this.folderSuccessMessage = "Folder renamed to: " + this.folderName;
        this.isFolderItemVisible = true;
    }).catch(err => {
        // Error!
    });

Improve this document

Demo Source

File Properties

File Methods

Folder Properties

Folder Methods

knownFolders Methods

path Methods

API References