@lucadani7/algonodejs-for-beginners/dist/ErathostenesSieve.js

Just a simple Node.js package with some basic algorithms perfect for people just starting out. It's got easy-to-understand TypeScript versions of stuff like sorting, searching, math with numbers, and messing with strings.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.ErathostenesSieve = void 0;
class ErathostenesSieve {
    static deleteElemFromSieve(ourList, value) {
        ourList[value >> 3] &= ~(1 << (value & 7));
    }
    static checkElemFromSieve(ourList, value) {
        return (ourList[value >> 3] & (1 << (value & 7))) !== 0;
    }
    static primesGenerator(value) {
        let primesArray = new Array();
        primesArray.push(2);
        const dim = Math.floor(value / 16) + 1;
        let ourList = new Array(dim);
        ourList.fill(0xFF, 0, dim);
        for (let i = 1; ((i * i) << 1) + (i << 1) <= value; ++i) {
            // if 2 * i + 1 is prime
            if (this.checkElemFromSieve(ourList, i)) {
                for (let j = ((i * i) << 1) + (i << 1); (j << 1) + 1 <= value; j += (i << 1) + 1) {
                    this.deleteElemFromSieve(ourList, j); // delete multiples of 2 * i + 1
                }
            }
        }
        for (let i = 1; (i << 1) + 1 <= value; ++i) {
            if (this.checkElemFromSieve(ourList, i)) {
                primesArray.push((i << 1) + 1);
            }
        }
        return primesArray;
    }
    static erathostenesIntervalGenerator(start, end) {
        const startValue = Math.min(start, end);
        const endValue = Math.max(start, end);
        return this.primesGenerator(endValue).filter(elem => elem >= startValue && elem <= endValue);
    }
}
exports.ErathostenesSieve = ErathostenesSieve;