Scramble string N times in Node.JS

let myStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz\\\"";

function scramble(str, times) {

    str = Buffer.from(str, 'utf8');

    console.log(str + " >>>----> " + str.length + " chars");

    for (let i = 1; i <= times; i++) {

        let orig = Math.floor(Math.random() * str.length);
        let dest = Math.floor(Math.random() * str.length);

        let temp = str[orig];
        str[orig] = str[dest];
        str[dest] = temp;

    }

    console.log(str + " >>>----> " + str.length + " chars");
}

scramble(myStr, 223);

Expected output (mileage may vary):

ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz\" >>>----> 64 chars
4RjeE6DzBtYGAFTrbymnxIZXNq9c0kV"sUWhPiLKg\avJfSHl72p385uCwOdQM1o >>>----> 64 chars