How to reverse a negative integer in javascript?

So I came across a problem "How to reverse an integer in javascript?" I successfully managed to reverse the positive numbers for eg if I enter 123 then I get the output 321 but on the hand, if I am trying some negative number like -123 then I get 0 as the output. How can I solve this issue and get output as -321?

var reverse = function(x){
    let a = 0;
    while(x>0){
        a = a * 10 + x%10; 
        // 0 = 0 *10 + 123%10 = 3
        // a=3
        // 0 = 0 *10 + 12%10 = 2
        // a=2
        // 0 = 0*10 + 1%10 = 1
        // a=1
        x = Math.floor(x/10)
         //  x = 123/10 = 12
        //  x = 12/10 =1
    }
    console.log(a);
    return a;
}
var x = -123;
reverse(x)

>Solution :

Just Preserve the sign of an integer, like

var reverse = function(x){
    let sign = x<0?-1:1;
    let a = 0;
    x=Math.abs(x);
    while(x>0){
        a = a * 10 + x%10; 
        // 0 = 0 *10 + 123%10 = 3
        // a=3
        // 0 = 0 *10 + 12%10 = 2
        // a=2
        // 0 = 0*10 + 1%10 = 1
        // a=1
        x = Math.floor(x/10)
         //  x = 123/10 = 12
        //  x = 12/10 =1
    }
    console.log(sign*a);
    return a;
}
var x = -123;
reverse(x)