(function () { function isPrime(p) { const upper = Math.sqrt(p); for(let i = 2; i <= upper; i++) { if (p % i === 0 ) { return false; } } return true; } // Return n-th prime function prime(n) { if (n < 1) { throw Error("n too small: " + n); } let count = 0; let result = 1; while(count < n) { result++; if (isPrime(result)) { count++; } } return result; } console.log("your prime is ", prime(100000)); }());