JavaScript 寻找素数

isPrime.js

"use strict";

function primes_with_generator(start, max){
    // start: int ( start >= 2 )
    // max  : int
    if ( start < 2 ) throw new Error("start > 2 | start == 2");
    var generator = function* (start, max){
        var n = start || 2;
        while ( n <= max ){
            yield n++;
        }
    };
    var isPrime = function (n){
        var _is_prime = true;
        for (let i=2; i<=Math.floor(Math.sqrt(n)); i++){
            if ( n % i == 0 ){
                _is_prime = false;
                break;
            }
        }
        return _is_prime;
    };

    var gen    = generator(start, max);
    var result = [];

    while (true){
        let next = gen.next();
        if ( next.done ) break;
        let is_prime = isPrime(next.value);
        if ( is_prime ) result.push(next.value);
    }
    return result;
}

function primes (n, max){
    // n  : int ( n >= 2 )
    // max: int
    if ( n < 2 ) throw new Error("n > 2 | n == 2");
    var is_prime = true;
    // WARN: RangeError: Maximum call stack size exceeded 
    for (let i=2; i<=Math.floor(Math.sqrt(n)); i++){
        if ( n % i == 0 ){
            is_prime = false;
            break;
        }
    }
    
    var result;
    if ( n == max ) {
        result = is_prime ? [n] : [];
    } else {
        result = is_prime ? [n].concat(primes(n+1, max)) : primes(n+1, max);
    }
    return result;
}

function test_primes_with_generator(){
    let start  = 2;
    let max    = 100;
    let result = primes_with_generator(start, max);
    console.log(JSON.stringify(result));
}
function test_primes(){
    let start  = 2;
    let max    = 10;
    let result = primes(start, max);
    console.log(JSON.stringify(result));
}

function test(){
    test_primes();
    test_primes_with_generator();
}

test();