Standard library for JavaScript runtimes.
A standard library for JavaScript runtimes, consistently working across Node, Deno, Bun and future runtimes.
| Package | Purpose |
|---|---|
| @rcompat/args | Program arguments |
| @rcompat/array | Arrays |
| @rcompat/assert | Assertions |
| @rcompat/cli | CLI tools |
| @rcompat/crypto | Cryptographic functions |
| @rcompat/env | Environment variables |
| @rcompat/fs | Filesystem access |
| @rcompat/fn | Function handling |
| @rcompat/html | HTML handling |
| @rcompat/http | HTTP servers |
| @rcompat/proby | Test runner |
| @rcompat/dict | Dictionaries |
| @rcompat/runtime | Runtime detection |
| @rcompat/sql | SQL |
| @rcompat/io | Input/output |
| @rcompat/stream | Streams |
| @rcompat/string | Strings |
| @rcompat/test | Testing |
| @rcompat/type | Types |
| @rcompat/webview | Webview |
| @rcompat/worker | Workers |
While tools like Bun strive to be fully compatible with Node's built-in modules and NPM, with Deno also moving in that direction, those backwards compatibilities carry a lot of cruft and in the end, you're just using another runtime to run code written for Node, without taking advantage of the inherent speed gains that modern APIs introduce. rcompat abstracts that away for you. You write code once and, wherever possible, it will take advantage of native APIs. This allows you not only to run the same code with different runtimes, but also speed it up if you choose Bun or Deno over Node during production. You can easily switch between the runtimes, testing stability vs. modern features, finding the best runtime for a given app.
rcompat offers forward compatibility in the sense that it can add support for new runtimes as they emerge even on minor updates (as this isn't considered breaking existing code), allowing you to run old code that was written with rcompat by newer runtimes. No other server-side interoperability layer for JavaScript offers this kind of flexibility.
rcompat is designed with many modules in mind, including @rcompat/fs for
filesystem operations, @rcompat/http for using a modern HTTP server working
with WHATWG Request/Response (which Node doesn't support; rcompat wraps
a Node request object into a WHATWG Request as it comes in),
@rcompat/invariant for ensuring runtime invariants, @rcompat/record for
record handling, and many more useful modules and abstractions.
The standard library is designed to accommodate modern development needs: for
example, @rcompat/http supports WebSockets (natively on Deno/Bun, and using
NPM's ws on Node), while @rcompat/fs/FileRef offers globbing, listing and
manipulation of files, similarly to Python's pathlib.
For example, to set up a server with rcompat, use @rcompat/http/serve -- the
server-side equivalent of fetch.
import serve from "@rcompat/http/serve";
serve(request => new Response("Hi!"), { host: "localhost", port: 6161 });This code runs successfully with either node app.js (if you set your
package.json to { "type": "module" }; otherwise use app.mjs), deno run -A app.js or bun --bun app.js, taking advantage of native optimizations.
The JavaScript ecosystem is replete with standard libraries. To take the example of filesystem access, Node has at least three ways of accessing the filesystem (sync, callbacks, promises), and then there's Deno's own filesystem APIs, while Bun has its APIs too. Those all have their pros and cons, and if you want to target all of them, you're going to have to write a lot of branching code. rcompat is an abstraction over that, as it plays the role of both a standard library and a runtime compatibility layer -- write once, target everything.
For example, here's how you can read a file and parse it as JSON.
import FileRef from "@rcompat/fs/FileRef";
console.log(await new FileRef("./users.json").json());Again, this code runs successfully on Node, Deno or Bun, taking advantage of optimizations native to every runtime.
rcompat has been quietly developed the last few months in conjunction with Primate's development and is largely influenced by its needs. We'd like to invite more participation by other projects / individuals in order to converge on APIs that best serve everyone and are the most useful on a broad basis.
- Discord: https://discord.gg/RSg4NNwM4f
MIT
See Hacking