@thi.ng/strings/units.js

Various string formatting & utility functions

import { memoizeJ } from "@thi.ng/memoize/memoizej";
const units = memoizeJ(
  (exp, base, prec = 2) => {
    const groups = exp.map(
      (x) => [
        x[0],
        x[2] != null ? x[2] : prec,
        x[1]
      ]
    ).sort((a, b) => a[0] - b[0]);
    return (x) => {
      if (x === 0) {
        return `0${base}`;
      }
      const absX = Math.abs(x);
      for (let i = groups.length; i-- > 0; ) {
        const g = groups[i];
        if (absX >= g[0] || i === 0) {
          return (x / g[0]).toFixed(g[1]) + g[2];
        }
      }
      return "";
    };
  }
);
const KB = 1024;
const bits = units(
  [
    [1, " bits", 0],
    [KB, " Kb"],
    [KB ** 2, " Mb"],
    [KB ** 3, " Gb"]
  ],
  " bits",
  2
);
const bytes = units(
  [
    [1, " bytes", 0],
    [KB, " KB"],
    [KB ** 2, " MB"],
    [KB ** 3, " GB"],
    [KB ** 4, " TB"],
    [KB ** 5, " PB"]
  ],
  " bytes",
  2
);
const seconds = units(
  [
    [1e-12, " ps"],
    [1e-9, " ns"],
    [1e-6, " \xB5s"],
    [1e-3, " ms"],
    [1, " secs"],
    [60, " mins"],
    [60 * 60, " hours"],
    [24 * 60 * 60, " days"]
  ],
  " secs",
  3
);
const meters = units(
  [
    [1e-12, " pm"],
    [1e-9, " nm"],
    [1e-6, " \xB5m"],
    [1e-3, " mm"],
    [0.01, " cm"],
    [1, " m"],
    [1e3, " km"]
  ],
  " m",
  2
);
const grams = units(
  [
    [1e-12, " pg"],
    [1e-9, " ng"],
    [1e-6, " \xB5g"],
    [1e-3, " mg"],
    [1, " g"],
    [1e3, " kg"],
    [1e6, " t"],
    [1e9, " kt"],
    [1e12, " Mt"]
  ],
  " g",
  2
);
const unitless = units(
  [
    [1e-15, "f", 1],
    [1e-12, "p", 1],
    [1e-9, "n", 1],
    [1e-6, "\xB5", 1],
    [1e-3, "m", 1],
    [1, ""],
    [1e3, "k", 1],
    [1e6, "M", 1],
    [1e9, "G", 1],
    [1e12, "T", 1],
    [1e15, "P", 1]
  ],
  "",
  0
);
export {
  bits,
  bytes,
  grams,
  meters,
  seconds,
  unitless,
  units
};