Random object generator in JavaScript

Question

I need a random object generator in JavaScript that generates a variety of objects with different fields and values. Any ideas where I can find such tool?

I need to generate random objects with various complexity.. My goal is to use JSON in order to serialize these objects and fuzz test my application http api.

Um... Write it? Or clarify your needs, because they sound very specific to me. — Ricket, Mar 14 '10 at 21:47
I need to generate random objects with various complexity.. My goal is to use JSON in order to serialize these objects and fuzz test my application http api. — Gjorgji, Mar 14 '10 at 22:07

score 9 · Accepted Answer · edited Jun 14 '14 at 21:17

function createRandomObj(fieldCount, allowNested)
{
    var generatedObj = {};

    for(var i = 0; i < fieldCount; i++) {
        var generatedObjField;

        switch(randomInt(allowNested ? 6 : 5)) {

            case 0:
            generatedObjField = randomInt(1000);
            break;

            case 1:
            generatedObjField = Math.random();
            break;

            case 2:
            generatedObjField = Math.random() < 0.5 ? true : false;
            break;

            case 3:
            generatedObjField = randomString(randomInt(4) + 4);
            break;

            case 4:
            generatedObjField = null;
            break;

            case 5:
            generatedObjField = createRandomObj(fieldCount, allowNested);
            break;
        }
        generatedObj[randomString(8)] = generatedObjField;
    }
    return generatedObj;
}

// helper functions

function randomInt(rightBound)
{
    return Math.floor(Math.random() * rightBound);
}

function randomString(size)
{
    var alphaChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
    var generatedString = '';
    for(var i = 0; i < size; i++) {
        generatedString += alphaChars[randomInt(alphaChars.length)];
    }

    return generatedString;
}

It will create a obj with X paramenters, all with a integer, float, string, boolean or null value.
I just made it :B

Will it work if I set the value for one field to be an object: o[getRandomString(8)]=createRandomObj(5) I want to get more complex object generated.. something like: {"a":3,"b":{"c":4,"d":5}} — Gjorgji, Mar 14 '10 at 23:41
See second paramenter :), if it is true, it will make subobjects with using the same function and paramenters :) — , Mar 15 '10 at 01:39
Be careful with this - as far as i see, if fieldCount > 5 and allowNested = true, this will likely run forever at it may try to generate objects with infinite depth. — leumasme, Aug 24 '21 at 11:59

score 3 · Answer 2 · answered Mar 01 '19 at 17:39

You can use hasard library

Random variables and random nested objects manipulation in javascript

const h = require('hasard');

const randomInteger = h.integer({type: 'poisson', lambda: 4});

const randomString = h.string({
    size: h.add(randomInteger, 5),
    value: h.value('abcdefghijklmnopkrstuvw'.split(''))
});

const randomNumber = h.number([0, 100]);

const randomKeys = h.array({
    size: randomInteger,
    value: randomString
});

// we first define it, to use it as reference into randomObject
const randomValue = h.value();

const randomObject = h.object(
    randomKeys,
    randomValue
);

// And we set recursivity by setting his values afterward
randomValue.set([
    randomString,
    randomObject,
    randomNumber,
    randomInteger
]);

Results will looks like

[
  {
    "vbmujvv": "rfigcpcvpj",
    "sjmcgvvk": 3,
    "efdarehl": {
      "odinthsuca": "rwjhmbfus",
      "noihjtjen": 27.73332043042913,
      "brspkaagb": "lnuiabcfd"
    },
    "febtungjhfokf": 49.28625818957401,
    "eoemrkgi": {
      "jkcuwrpsh": "ekjoltm",
      "cincs": {
        "fcovbwk": {
          "whsgmjh": 48.00843935524626,
          "agsjflef": 46.700796253998014
        },
        "ovkdfudgfm": 84.83383163217746,
        "fpfetl": "djuvfjbjptf",
        "kobmkstj": {
          "wskgkkerk": 9,
          "kvnptptek": 37.63655947554132,
          "dsloun": 4
        }
      },
      "krirwk": {
        "sjgftomu": 51.663884142674775,
        "hpjgibnli": 4
      },
      "pkhkgruls": "isuodwjrg"
    },
    "ortomnue": 71.71303423929236
  }
]

DISCLAIMER i'm the author of hasard library

The recursive calls to `randomObject` in the `randomValue` can easily cause stack overflows. Something to be aware of, maybe fix with a max depth or something if possible. Nice library, thank you! :) — jocull, Jul 17 '23 at 04:22

Random object generator in JavaScript

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