src/js/util/helper.js
function precision(a) {
  // http://stackoverflow.com/a/27865285/1181761

  // guard for NaN
  if (a === a) {
		var e = 1;
		while (Math.round(a * e) / e !== a) e *= 10;
		return Math.round(Math.log(e) / Math.LN10);
  } else {
		return 0;
  }
}
function precision(a) {
  // http://stackoverflow.com/a/27865285/1181761

  // guard for NaN
  if (a === a) {
		var e = 1;
		while (Math.round(a * e) / e !== a) e *= 10;
		return Math.round(Math.log(e) / Math.LN10);
  } else {
		return 0;
  }
}
precision

@param a
@static
@memberof helper
@return {undefined}