function uuid() {

  // Public Domain/MIT

  var d = new Date().getTime(); //Timestamp

  var d2 =

    (typeof performance !== "undefined" &&

      performance.now &&

      performance.now() * 1000) ||

    0; //Time in microseconds since page-load or 0 if unsupported

  return "xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx".replace(/[xy]/g, function (c) {

    var r = Math.random() * 16; //random number between 0 and 16

    if (d > 0) {

      //Use timestamp until depleted

      r = (d + r) % 16 | 0;

      d = Math.floor(d / 16);

    } else {

      //Use microseconds since page-load if supported

      r = (d2 + r) % 16 | 0;

      d2 = Math.floor(d2 / 16);

    }

    return (c === "x" ? r : (r & 0x3) | 0x8).toString(16);

  });

}

​

function shortId() {

  // I generate the UID from two parts here

  // to ensure the random number provide enough bits.

  let firstPart = (Math.random() * 46656) | 0;

  let secondPart = (Math.random() * 46656) | 0;

  firstPart = ("000" + firstPart.toString(36)).slice(-3);

  secondPart = ("000" + secondPart.toString(36)).slice(-3);

  return firstPart + secondPart;

}

​

function shuffle(array) {

  let currentIndex = array.length,

    randomIndex;

​

  // While there remain elements to shuffle.

  while (currentIndex != 0) {

    // Pick a remaining element.

    randomIndex = Math.floor(Math.random() * currentIndex);

    currentIndex--;

​

    // And swap it with the current element.

    [array[currentIndex], array[randomIndex]] = [

      array[randomIndex],

      array[currentIndex],

    ];

  }

​

  return array;

}

​

const NB_ITEMS = 100000;

var objectWithVeryShortKeys = {};

var veryShortKeys = [];

for (let i = 0; i < NB_ITEMS; i++) {

  let key = shortId();

  objectWithVeryShortKeys[key] = Math.random();

  veryShortKeys.push(key);

}

​

var objectWithShortKeys = {};

var shortKeys = [];

for (let i = 0; i < NB_ITEMS; i++) {

  let key = uuid();

  objectWithShortKeys[key] = Math.random();

  shortKeys.push(key);

}

​

var objectWithMediumKeys = {};

var mediumKeys = [];

for (let i = 0; i < NB_ITEMS; i++) {

  let key = `${uuid()}::${uuid()}`;

  objectWithMediumKeys[key] = Math.random();

  mediumKeys.push(key);

}

​

var objectWithLongKeys = {};

var longKeys = [];

for (let i = 0; i < NB_ITEMS; i++) {

  let key = `${uuid()}::${uuid()}::some_more_text::${uuid()}`;

  objectWithLongKeys[key] = Math.random();

  longKeys.push(key);

}

​

var objectWithVeryLongKeys = {};

var veryLongKeys = [];

for (let i = 0; i < NB_ITEMS; i++) {

  let key = `${uuid()}::${uuid()}::some_more_text::${uuid()}::${uuid()}::${uuid()}::some_more_text::${uuid()}`;

  objectWithVeryLongKeys[key] = Math.random();

  veryLongKeys.push(key);

}

​

shuffle(veryShortKeys);

shuffle(shortKeys);

shuffle(mediumKeys);

shuffle(longKeys);

shuffle(veryLongKeys);