Runtime Detection Utility

A lightweight TypeScript utility that detects the current JavaScript runtime environment (Deno, Node.js, Bun, or Browser).

Installation

deno add jsr:@online/runtime

Usage

import { EngineType, getRuntime } from "@online/runtime";

const currentRuntime = getRuntime();

switch (currentRuntime) {
  case EngineType.Deno:
    console.log("Running in Deno");
    break;
  case EngineType.Node:
    console.log("Running in Node.js");
    break;
  case EngineType.Bun:
    console.log("Running in Bun");
    break;
  case EngineType.Browser:
    console.log("Running in Browser");
    break;
  default:
    console.log("Unknown runtime environment");
}

API Reference

EngineType

An enum representing different JavaScript runtime environments:

enum EngineType {
  Deno = "deno",
  Node = "node",
  Bun = "bun",
  Browser = "browser",
  Unknown = "unknown",
}

getRuntime()

Returns the current runtime environment as an EngineType.

Returns:

• EngineType.Deno - When running in Deno
• EngineType.Node - When running in Node.js
• EngineType.Bun - When running in Bun
• EngineType.Browser - When running in a browser environment
• EngineType.Unknown - When the runtime cannot be determined

How it Works

The utility determines the runtime environment by checking for the existence of runtime-specific global variables:

1. Checks for Deno global object (Deno)
2. Checks for Bun global object (Bun)
3. Checks for process.versions.node (Node.js)
4. Checks for window object (Browser)
5. Returns Unknown if none of the above are detected

TypeScript Support

This utility is written in TypeScript and includes type definitions out of the box.

License

MIT (or specify your chosen license)

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.