Eratosthenes筛

Posted 2021-02-25

Returns an array of all the prime numbers up to (n) using an implementation of the Sieve of Eratosthenes.

var getPrimes = function (n) {
    var numbers = [],
        multiple, i, j, len,
        square = function (x) { return x * x; };
 
    for(i = 2; i <= n; i++) {
        numbers.push(i);
    }
 
    for(j = 0; square(numbers[j]) < n; j++) {
        multiple = numbers[j];
        for(i = 0, len = numbers.length; i < len; i++) {
            if(numbers[i] % multiple === 0) {
                if(numbers[i] === multiple) { i++; continue; }
                numbers.splice(i, 1);
            }
        }
    }
    return numbers;
};