js outputs prime numbers within 100

1. The definition of prime numbers

    If an integer can only be divisible by 1 and itself, then the number is a prime number.
    Note that 1 is not a prime number, nor is it an even number.

2. The method of judging prime numbers

• 2.1 Take the square of an integer n to get sqrt(n)
• 2.2 Choose an integer in [2, sqrt(n)] to divide n. If it can be divided evenly, it means that n is not a prime number. If there is no divisible one, then n is a prime number.

3. js language realizes prime number judgment

 //5.1) 判断质数
    function getPrimes(arr) {
    
    
        return arr.filter(function (ele) {
    
    
           if (ele == 1) {
    
    
               return  false;
           }

           for (var i=2; i<=Math.sqrt(ele); i++) {
    
    
               if (ele % i == 0) {
    
    
                   return false;
               }
           }

           return true;
        });
    }

    //5.2) 初始化参数
    var arr = [];
    for (var x=1; x<=100; x++) {
    
    
        arr.push(x);
    }
    var num = getPrimes(arr);

    //5.3) 每行10个元素，进行打印
    let line = [];
    for (var i=0; i<num.length; i++) {
    
    
        line.push(num[i]);
        if ((i+1)%10 == 0){
    
    
            console.log(line);
            line = [];
        }
    }

    //5.4) 手动验证质数
    var bRet2 = (num.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("check ",bRet2)

    The effect is as follows:

Figure (1) Find prime numbers within 100