@santi100/eratosthenes-sieve/cjs/index.js

Santi's Energetic Sieve of Eratosthenes: How can you sift numbers?

"use strict";
var assertExclusiveMin = require("@santi100/assertion-lib/cjs/exclusive-min");
var assertTypeOf = require("@santi100/assertion-lib/cjs/type-of");
var assertInteger = require("@santi100/assertion-lib/cjs/integer");
var assertPositive = require("@santi100/assertion-lib/cjs/positive");
/**
 * Finds all prime numbers from 2 up to a given number `n`.
 *
 * @param n The upper limit of the range of numbers to check for primes.
 */
function sieve(n) {
    assertTypeOf(n, 'number', 'n');
    assertInteger(n, 'n');
    assertPositive(n, 'n');
    assertExclusiveMin(n, 1, 'n');
    if (n === 2)
        return [n];
    var numbers = {};
    var limit = Math.floor(Math.pow(n, 0.5));
    for (var i = 2; i <= n; i++)
        numbers[i] = false;
    for (var i = 2; i <= limit; i++) {
        if (!numbers[i]) {
            for (var j = i; j <= n / i; j++) {
                numbers[i * j] = true;
            }
        }
    }
    var results = [];
    for (var num in numbers) {
        if (!numbers[num])
            results.push(Number(num));
    }
    return results;
}
module.exports = sieve;