d3-random using ramdajs

random.js

import R from 'ramda';

const rRandom = (x = Math.random() * 2 - 1, y = Math.random() * 2 - 1) => {
  const r = x * x + y * y;

  if (!r || r > 1) return rRandom();
  else return { x: x, r: r };
}

const normal = (µ = 0, σ = 1) => {
  const rr = rRandom();

  return µ + σ * rr.x * Math.sqrt(-2 * Math.log(rr.r) / rr.r);
};

const logNormal = R.compose(Math.exp, normal);

const irwinHall = R.compose(
  R.reduce((a, b) => (a + b), 0),
  R.times(() => Math.random())
);

const bates = m => irwinHall(m) / m;

export default {
  normal:    R.curry(normal),
  logNormal: R.curry(logNormal),
  irwinHall: R.curry(irwinHall),
  bates:     R.curry(bates)
}