@mjackson/file-storage NPM

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