blob: b161eca7ad910561db5914f2b4f72d2b6666f845 [file] [log] [blame]
// Parts of implementation taken from es6-shim project
// See: https://github.com/paulmillr/es6-shim/blob/master/es6-shim.js
"use strict";
var expm1 = require("../expm1")
, abs = Math.abs
, exp = Math.exp
, e = Math.E;
module.exports = function (value) {
if (isNaN(value)) return NaN;
value = Number(value);
if (value === 0) return value;
if (!isFinite(value)) return value;
if (abs(value) < 1) return (expm1(value) - expm1(-value)) / 2;
return ((exp(value - 1) - exp(-value - 1)) * e) / 2;
};