mu-conv

UCUM unit conversion for JavaScript, powered by the mu Go library compiled to WebAssembly. Converts quantities between commensurable units in three numeric formats: float64, exact rationals, and fixed-precision decimals at 34 significant digits.

Install

npm install mu-conv

Usage

import { load } from "mu-conv";

const mu = await load();  // hydrate the embedded data tables, ~7 ms

mu.convert(1, "kg", "[lb_av]");             // 2.2046226218487757 (number)
mu.convertString("1", "kg", "[lb_av]");     // "2.2046226218487757"
mu.convertRational("1", "m", "cm");         // "100" (exact)
mu.convertDecimal("100", "Cel", "[degF]");  // "212"
mu.convertString("1", "KG", "G", { caseInsensitive: true });

mu.validate("kg.m/s2");  // returns undefined; throws on invalid
mu.commensurable("B[W]", "W");  // true: dimensioned special unit

convert takes and returns a JS number (float64); the other functions take values as strings and return strings. All throw Error on failure.

load() instantiates the bundled module once and memoizes it; concurrent callers share the instance. A failed load is not cached, so it can be retried.

Numeric formats

• convert — numeric fast path using native JS number (float64) values
• convertString — accepts anything parseFloat would; returns Go's 'g' shortest-round-trip format
• convertRattional — accepts fraction syntax ("3/2", "1.5", "1e10") and returns an exact fraction as a string
• convertDecimal — 34 significant digits, rendered in plain decimal notation as a string

License

BSD-3-Clause. The embedded UCUM tables carry their own terms — see LICENSE-UCUM.md.