ljs password generator

gen-pass.js

#! /usr/bin/env ljs

var range   = (arguments.shift() || "15-20").split(/-/);
var charset = new RegExp(arguments.shift() || "[a-zA-Z0-9]");
var regex   = new RegExp(arguments.shift() || ".");

var length = ((Math.random() * (range[1].toNumber() - range[0].toNumber())) + range[0].toNumber()).ceil();

do {
    var password = "";

    for (let i = 0; i < length; i++) {
        let ch = String.fromCharCode(Math.random() * 200+10);

        if (ch.test(charset)) {
            password += ch;
        }
        else {
            i--;
        }
    }
} while (!password.test(regex));

print(password);