This is an implementation of the sieve of Eratosthenes. It finds prime numbers for you.

npm install sieve

varsieve=require('sieve');// primes from 2 to 1000000varprimes=sieve(1000000);// primes from 100 to 1000000varprimes=sieve(1000000,100);

The sieve returns a Uint32Array, unless you are using a terrible browser, in which case you just get an ordinary array.

On my macbook pro, it found all primes from 2 to 100,000,000 in 2723ms.

It has memory issues with arrays much larger than that. If that is a problem, submit a pull request.