JavaScript 筛选素数.md

// 声明
'use strict';

function get_primes(arr) {
    return arr.filter(function (element){
        // 判输入值非数字
        if (typeof element !== 'number'){
            throw 'Not a number!';
        }
        if (element < 2) {
            return false;
        }
        if (element ===2) {
            return true;
        }
        var res = true;
        // 循环判定
        for (var i = 2; i < element; i++) {
            if (element % i === 0) {
                res = false;
                break;
            }
        } return res;
    })
}

// 测试:
var
    x,
    r,
    arr = [];
for (x = 1; x < 100; x++) {
    arr.push(x);
}
r = get_primes(arr);
if (r.toString() === [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97].toString()) {
    console.log('测试通过!');
} else {
    console.log('测试失败: ' + r.toString());
}