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DTRExp

Implementations

Six implementations, each developed clean-room against the conformance vectors; built from the prose and vectors alone, with every divergence between them resolved as a spec fix and a new vector. All zero-dependency. The Rust core additionally ships as a WASM package for browsers and JS runtimes.

They share one API vocabulary; operation names are fixed as words (covers, covers in, to rrule) and rendered in each language’s casing convention. Learn one library and you know them all.

Language Package Install Requires
TypeScript / JavaScript (reference) dtrexp on npm npm i dtrexp Node.js ≥ 20
WebAssembly (the Rust core) dtrexp-wasm on npm npm i dtrexp-wasm any modern browser or JS runtime
Python dtrexp on PyPI pip install dtrexp Python 3.11+
Go dtrexp-go via the Go proxy go get github.com/DTRExp/dtrexp-go Go 1.26+
Rust dtrexp on crates.io cargo add dtrexp Rust 2021 edition
Swift dtrexp-swift via SwiftPM .package(url: "https://github.com/DTRExp/dtrexp-swift", from: "1.0.0") Swift 6.0+
Java io.onury:dtrexp on Maven Central implementation("io.onury:dtrexp:1.0.1") Java 17+

Each language has its own page with install, worked examples and the full member table:

  • JavaScript / TypeScript (dtrexp-js) — the reference implementation. TypeScript, ESM, zero runtime dependencies.
  • WASM (dtrexp-wasm) — the Rust core via wasm-bindgen; ~63 KB wasm, ~29 KB gzipped, instantiates at import. IANA zones come from the host’s Intl data, so no timezone database is bundled.
  • Python (dtrexp-py) — stdlib only; zoneinfo for IANA zones.
  • Go (dtrexp-go) — stdlib only; time for IANA zones.
  • Rust (dtrexp-rs) — no dependencies, including the zone handling; IANA zones are read straight from the system TZif database.
  • Swift (dtrexp-swift) — Foundation only; TimeZone and Date for zones and instants.
  • Java (dtrexp-java) — pure Java 17+, zero dependencies; java.time for IANA zones.

Building your own? Start from the library interface and wire in the vectors; an implementation that passes vectors.json is a conforming DTRExp implementation, whatever its internals look like.