function oldmeth() {

  function chr4 () {

    return Math.random().toString(16).slice(-4);

  }

  return `${chr4() + chr4()}-${chr4()}-${chr4()}-${chr4()}-${chr4()}${chr4()}${chr4()}`;

}

​

function oldmethcrypto() {

  function getRandom () {

    return crypto.getRandomValues(new Uint32Array(4)).reduce((prev, current) => `${prev.toString(16)}${current.toString(16)}`);

  }

  function update4(uuid) {

    const fourIndx = 12;

    return `${uuid.slice(0,12)}4${uuid.slice(13)}`;

  }

  function getEight(c) {

    return(c ^ crypto.getRandomValues(new Uint8Array(1))[0] & 15 >> c / 4).toString(16);

  }

  function update8(uuid) {

    const eightIndx = 16;

    return `${uuid.slice(0,16)}${getEight(8)}${uuid.slice(17)}`;

  }

  function addDashes(uuid) {

    // xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx

    return `${uuid.slice(0,8)}-${uuid.slice(8,12)}-${uuid.slice(12,16)}-${uuid.slice(16,20)}-${uuid.slice(20)}`;

  }

  let uuid = getRandom();

  uuid = update4(uuid);

  uuid = update8(uuid);

  uuid = addDashes(uuid);

  return uuid;

}

​

​

function oldmethcrypto2() {

  function getRandom () {

    return crypto.getRandomValues(new Uint32Array(4)).reduce((prev, current) => `${prev.toString(16)}${current.toString(16)}`);

  }

​

  function getEight(c) {

    return(c ^ crypto.getRandomValues(new Uint8Array(1))[0] & 15 >> c / 4).toString(16);

  }

​

  let uuid = getRandom();

  return `${uuid.slice(0,8)}-${uuid.slice(8,12)}-4${uuid.slice(13,16)}-${getEight(8)}${uuid.slice(17,20)}-${uuid.slice(20)}`;

}

​

function newmethrand1() {

  function getRandom (num) {

    let output;

    for(let i = 0; i < Math.ceil(num/8); i++) {

      output = `${output}${Math.random().toString(16).slice(-8)}`;

    }

    return output.slice(num * -1);

  }

​

  function getEight(c) {

    return(c ^ Math.random().toString(16).slice(-1) & 15 >> c / 4).toString(16);

  }

​

  let uuid = getRandom(32);

  return `${uuid.slice(0,8)}-${uuid.slice(8,12)}-4${uuid.slice(13,16)}-${getEight(8)}${uuid.slice(17,20)}-${uuid.slice(20)}`;

}

​

function newmeth() {

  return ([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, c =>

     (c ^ crypto.getRandomValues(new Uint8Array(1))[0] & 15 >> c / 4).toString(16),

  );                                      

}