@thi.ng/units/units/parts.js

Extensible SI unit creation, conversions, quantities & calculations (incl. ~170 predefined units & constants)

import { defUnit, dimensionless } from "../unit.js";
const percent = defUnit("%", "percent", dimensionless(0.01));
const permille = defUnit("\u2030", "permille", dimensionless(1e-3));
const permyriad = defUnit("\u2031", "permyriad", dimensionless(1e-4));
const pcm = defUnit("pcm", "part per cent mille", dimensionless(1e-5));
const ppm = defUnit("ppm", "part per million", dimensionless(1e-6));
const ppb = defUnit("ppb", "part per billion", dimensionless(1e-9));
const ppt = defUnit("ppt", "part per trillion", dimensionless(1e-12));
export {
  pcm,
  percent,
  permille,
  permyriad,
  ppb,
  ppm,
  ppt
};