Compatibility

API support matrix, WebAssembly compatibility, and polyfill status

Overview

NANO is a WinterTC-compatible runtime providing web-standard APIs (fetch, Request, Response) rather than Node.js-specific APIs (fs, path, http).

The nano-compat library provides polyfills for common Node.js patterns requiring backward compatibility.

WebAssembly Support

V8 built-in WASM engine executes binary modules without external dependencies.

Example
const wasmModule = await WebAssembly.compile(wasmBytes);
const instance = await WebAssembly.instantiate(wasmModule, {
  env: { memory: new WebAssembly.Memory({ initial: 1 }) }
});
const result = instance.exports.add(1, 2);

Capabilities

  • Module Compilation: WebAssembly.compile() for binary validation
  • Instantiation: WebAssembly.instantiate() with import objects
  • Memory Management: WebAssembly.Memory for linear memory
  • Table Imports: WebAssembly.Table for function references
  • Source Integrity: Hash-based caching for verification

WinterTC API Matrix

Implementation status of WinterTC standard APIs.

API Status Notes
fetch() Complete Full implementation with streaming
Request Complete Constructor with method, headers, body
Response Complete Constructor with status, headers, body
Headers Complete Map-like interface, case-insensitive
URL Complete Full URL parsing with all properties
URLSearchParams Complete Query string manipulation
TextEncoder Complete UTF-8 encoding to Uint8Array
TextDecoder Complete UTF-8 decoding from Uint8Array
ReadableStream Complete Streaming data interface
WritableStream Complete Output streaming with backpressure
crypto.getRandomValues Complete All TypedArray types supported
crypto.subtle.digest Complete SHA-256, SHA-384, SHA-512
crypto.subtle.generateKey Complete AES-GCM, HMAC
crypto.subtle.encrypt Complete AES-GCM with JWK keys
WebAssembly Complete V8 built-in WASM engine
console Complete log, error, warn, info, debug
setTimeout/setInterval Complete Timer functions with clearing
atob/btoa Complete Base64 encoding/decoding
structuredClone Complete Deep object cloning
WebSocketPair In Progress v2.0a — Phase 23. Cloudflare Workers compatible API.

Node.js Compatibility

Limited Node.js compatibility available via nano-compat polyfills.

Module Status Notes
assert Native WinterTC compatible
Buffer Polyfill Full implementation via nano-compat
fs Polyfill VFS-based filesystem (Nano.fs.*)
path Polyfill Path manipulation utilities
crypto (Node) Not Available Use WebCrypto crypto.subtle instead
http Not Available Use WinterTC fetch instead
https Not Available Use WinterTC fetch instead
net Not Available Raw sockets not supported
stream Partial Limited via nano-compat
url Native WinterTC compatible
util Native WinterTC compatible

Framework Compatibility

Verified framework support for WinterTC-compatible JavaScript frameworks.

Hono

Ultra-lightweight web framework

Fully Compatible

Astro

Static site generator with islands

Fully Compatible

Next.js

Static export only (no SSR)

Partial

nano-compat Library

Optional polyfills for Node.js APIs not part of WinterTC.

Usage
import '@nano-rs/compat';

Buffer

Node.js Buffer implementation with proper toString()

Complete

path

Path manipulation and normalization

Complete

fs

VFS-based filesystem operations

Complete

timers

setImmediate, nextTick polyfills

Basic
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