runtime-save

A lightweight JavaScript library that provides a unified file-saving interface across different JavaScript environments (browser and Node.js).

Features

• Environment Detection: Automatically detects whether your code is running in a browser or Node.js
• Browser Support:
  • Uses the modern File System Access API when available
  • Falls back to the download attribute method for broader compatibility
• Node.js Support: Saves files to the file system using the native fs module
• Flexible Content Types: Accepts Blob, string, or Buffer input types
• TypeScript Support: Fully typed API with TypeScript declarations included

Installation

# npm
npm install runtime-save

# pnpm
pnpm add runtime-save

Usage

Basic Example

import { saveFile } from "runtime-save";

// Save a string to a file
await saveFile("hello.txt", "Hello, World!");

// Save a Blob to a file (works in both browser and Node.js)
const blob = new Blob(["CSV data"], { type: "text/csv" });
await saveFile("data.csv", blob);

// In Node.js, you can also save a Buffer
const buffer = Buffer.from("Buffer content");
await saveFile("file.bin", buffer);

// Specify a save path (only works in Node.js)
await saveFile("report.pdf", pdfContent, "/path/to/save/directory/");

Browser Environment

In a browser, runtime-save will:

1. Try to use the File System Access API first (modern browsers)
2. Fall back to using an anchor tag with the download attribute

Node.js Environment

In Node.js, runtime-save will:

1. Convert the content to a Buffer if it isn't already
2. Save to the specified path or to the current working directory if no path is provided

API

saveFile(filename, content, savePath?)

Saves content to a file, with environment-appropriate behavior.

Parameters

• filename (string): The name of the file to be saved
• content (Blob | string | Buffer): The content to save
• savePath (string, optional): The directory where the file should be saved (Node.js only)

Returns

• Promise<void>: Resolves when the file has been saved

Browser Compatibility

• Modern Browsers (Chrome 86+, Edge 86+): Full support with File System Access API
• All Modern Browsers: Fallback support using download attribute

Contributing

Please see CONTRIBUTING guide for details on how to contribute to this project.

Code of Conduct

This project adheres to a Code of Conduct. By participating, you are expected to uphold this code.

License

This project is licensed under the MIT License.