phpjs/functions/math/asinh.js

php.js offers community built php functions in javascript

function asinh(arg) {
  // From: http://phpjs.org/functions
  // +   original by: Onno Marsman
  // *     example 1: asinh(8723321.4);
  // *     returns 1: 16.67465779841863
  return Math.log(arg + Math.sqrt(arg * arg + 1));
}