file-storage

file-storage is a key/value interface for storing File objects in JavaScript. Similar to how localStorage allows you to store key/value pairs of strings in the browser, file-storage allows you to store key/value pairs of files on the server.

Features

• Simple, intuitive key/value API (like Web Storage, but for Files instead of strings)
• A generic FileStorage interface that works for various large object storage backends (can be adapted to AWS S3, Cloudflare R2, etc.)
• Support streaming file content to and from storage
• Preserves all File metadata including file.name, file.type, and file.lastModified

Installation

Install from npm:

npm install @mjackson/file-storage

Usage

import { LocalFileStorage } from '@mjackson/file-storage/local';

let storage = new LocalFileStorage('./user/files');

let file = new File(['hello world'], 'hello.txt', { type: 'text/plain' });
let key = 'hello-key';

// Put the file in storage.
await storage.set(key, file);

// Then, sometime later...
let fileFromStorage = await storage.get(key);
// All of the original file's metadata is intact
fileFromStorage.name; // 'hello.txt'
fileFromStorage.type; // 'text/plain'

// To remove from storage
await storage.remove(key);

The FileStorage interface allows you to implement your own file storage for custom storage backends:

import { type FileStorage } from '@mjackson/file-storage';

class CustomFileStorage implements FileStorage {
  /**
   * Returns `true` if a file with the given key exists, `false` otherwise.
   */
  has(key: string): boolean | Promise<boolean> {
    // ...
  }
  /**
   * Puts a file in storage at the given key.
   */
  set(key: string, file: File): void | Promise<void> {
    // ...
  }
  /**
   * Returns the file with the given key, or `null` if no such key exists.
   */
  get(key: string): File | null | Promise<File | null> {
    // ...
  }
  /**
   * Removes the file with the given key from storage.
   */
  remove(key: string): void | Promise<void> {
    // ...
  }
}

Related Packages

• form-data-parser - Pairs well with this library for storing FileUpload objects received in multipart/form-data requests
• lazy-file - The streaming File implementation used internally to stream files from storage

License

See LICENSE