有没有人可以把这个java代码用javascript写一下，，

   int i = 0;
    String str = "       H ell o  Wo rl d        ";
    int length = str.length() - 1;

    char[] arr = str.toCharArray();
    while (arr[i] == ' ') {
        i++;
    }
    while (arr[length] == ' ') {
        length--;
    }
    String aa = "";
    for (int j = i; j <= length; j++) {
        aa = aa + arr[j];
    }
    System.out.println(aa);

var i = 0;
    var str = "       H ell o  Wo rl d        ";
    var length = str.length- 1; 
   
    while (str[i] == ' ') {
        i++;
    }
    while (str[length] == ' ') {
        length--;
    }
    var aa = "";
    for ( j = i; j <= length; j++) {
        aa = aa + str[j];
    }
    console.log(aa); // aa=str.substring(i,length+1)


// aa= str.trim() ;

   let i = 0;
    let str = "       H ell o  Wo rl d        ";
    let length = str.length - 1;
 
    const arr = str.split('');
    while (arr[i] == ' ') {
        i++;
    }
    while (arr[length] == ' ') {
        length--;
    }
    let aa = "";


    for (let j = i; j <= length; j++) {
        aa = aa + arr[j];
    }
   console.log(aa)