math-fround.js 878 Bytes
var sign = require('../internals/math-sign');

var abs = Math.abs;
var pow = Math.pow;
var EPSILON = pow(2, -52);
var EPSILON32 = pow(2, -23);
var MAX32 = pow(2, 127) * (2 - EPSILON32);
var MIN32 = pow(2, -126);

var roundTiesToEven = function (n) {
  return n + 1 / EPSILON - 1 / EPSILON;
};

// `Math.fround` method implementation
// https://tc39.es/ecma262/#sec-math.fround
// eslint-disable-next-line es/no-math-fround -- safe
module.exports = Math.fround || function fround(x) {
  var n = +x;
  var $abs = abs(n);
  var $sign = sign(n);
  var a, result;
  if ($abs < MIN32) return $sign * roundTiesToEven($abs / MIN32 / EPSILON32) * MIN32 * EPSILON32;
  a = (1 + EPSILON32 / EPSILON) * $abs;
  result = a - (a - $abs);
  // eslint-disable-next-line no-self-compare -- NaN check
  if (result > MAX32 || result != result) return $sign * Infinity;
  return $sign * result;
};