The Math acosh() static method returns the inverse hyperbolic cosine of a number.
console.log(Math.acosh(0.999999999999));
// NaN
console.log(Math.acosh(1));
// 0
console.log(Math.acosh(2));
// 1.3169578969248166
console.log(Math.acosh(2.5));
// 1.566799236972411