const randStr = (length, min, max) => String.fromCharCode(...Array(length).fill().map(() => Math.floor(Math.random() * (max - min + 1)) + min))
console.log(randStr(10, 65, 90));
console.log(randStr(10, 97, 122)) //output: "jxqjxqjxqj")); between lowercase a
// z (10 letters)