Upgrade to TypeScript 6.0 and module: nodenext to remove reference directives

[deyaaeldeen]

Upgrade TypeScript from 5.0 to 6.0 and switch module from "commonjs" to "nodenext". This eliminates the auto-generated /// <reference types="node" /> directives from the generated .d.ts files.

Problem

TypeScript 5.x automatically emits /// <reference types="node" /> in .d.ts output when source code imports from Node.js built-in modules ("net", "tls", "events"). These directives inject the entire @types/node global namespace into consumers' type context, causing conflicts in non-Node environments (React Native, browser, Cloudflare Workers).

Solution

TypeScript 6.0 fixed this behavior — it no longer emits redundant reference directives when explicit module imports already exist. Upgrading TypeScript and switching to module: "nodenext" eliminates the directives without any post-processing.

Changes

File	Change
package.json	typescript ~5.0.4 → ^6.0.2, @types/node ^16.0.0 → ^20.0.0
tsconfig.json	module: "commonjs" → "nodenext", added moduleResolution: "nodenext", added explicit types
lib/log.ts	import * as debugModule → import debugModule (nodenext CJS interop)
lib/awaitableSender.ts	NodeJS.Timer → ReturnType<typeof setTimeout> (deprecated in @types/node@20)
test/*.spec.ts	import * as rhea → import rhea (same)
.github/workflows/ci.yml	Node matrix [16.x, 18.x, 20.x] → [20.x, 22.x]
README.md	Node.js 6.x → 20.x minimum
changelog.md	Added 3.0.4 (Unreleased) entry

Results

• ✅ Zero /// <reference types="node" /> directives in generated typings
• ✅ Zero lib compilation errors
• ✅ All 63 tests passing

Related

• Replace /// <reference types="node" /> with explicit import type in typings rhea#446 / Replace /// <reference types="node" /> with explicit import type in typings rhea#447 — same fix for the rhea package (hand-written typings)

Fixes #120