//length: defines the length of characters to express in the string

const rand=()=>Math.random(0).toString(36).substr(2);
const token=(length)=>(rand()+rand()+rand()+rand()).substr(0,length);

console.log(token(40));
//example1:  token(10) => result: tsywlmdqu6
//example2:  token(40) => result: m4vni14mtln2547gy54ksclhcv0dj6tp9fhs1k10