JAVASCRIPT ticks.js

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = ticks;
exports.tickIncrement = tickIncrement;
exports.tickStep = tickStep;
var e10 = Math.sqrt(50),
  e5 = Math.sqrt(10),
  e2 = Math.sqrt(2);
function ticks(start, stop, count) {
  var reverse,
    i = -1,
    n,
    ticks,
    step;
  stop = +stop, start = +start, count = +count;
  if (start === stop && count > 0) return [start];
  if (reverse = stop < start) n = start, start = stop, stop = n;
  if ((step = tickIncrement(start, stop, count)) === 0 || !isFinite(step)) return [];
  if (step > 0) {
    let r0 = Math.round(start / step),
      r1 = Math.round(stop / step);
    if (r0 * step < start) ++r0;
    if (r1 * step > stop) --r1;
    ticks = new Array(n = r1 - r0 + 1);
    while (++i < n) ticks[i] = (r0 + i) * step;
  } else {
    step = -step;
    let r0 = Math.round(start * step),
      r1 = Math.round(stop * step);
    if (r0 / step < start) ++r0;
    if (r1 / step > stop) --r1;
    ticks = new Array(n = r1 - r0 + 1);
    while (++i < n) ticks[i] = (r0 + i) / step;
  }
  if (reverse) ticks.reverse();
  return ticks;
}
function tickIncrement(start, stop, count) {
  var step = (stop - start) / Math.max(0, count),
    power = Math.floor(Math.log(step) / Math.LN10),
    error = step / Math.pow(10, power);
  return power >= 0 ? (error >= e10 ? 10 : error >= e5 ? 5 : error >= e2 ? 2 : 1) * Math.pow(10, power) : -Math.pow(10, -power) / (error >= e10 ? 10 : error >= e5 ? 5 : error >= e2 ? 2 : 1);
}
function tickStep(start, stop, count) {
  var step0 = Math.abs(stop - start) / Math.max(0, count),
    step1 = Math.pow(10, Math.floor(Math.log(step0) / Math.LN10)),
    error = step0 / step1;
  if (error >= e10) step1 *= 10;else if (error >= e5) step1 *= 5;else if (error >= e2) step1 *= 2;
  return stop < start ? -step1 : step1;
}