How to use random string as JSON object name

Question

I am trying to create a JSON object, with a random string as the name, just like how Firebase does it.

Goal: replace child name with random string.

For example:

"Users" : {
    "mGKgNDOw0qd77m6tmdDh76zOQOm2" : {
      "email" : "[email protected]",
      "firstName" : "some",
      "lastName" : "user",
      "username" : "someuser"
    },
    "vyMiCS7olNPh9bCXoKWqcIFNWVy2" : {
      "email" : "[email protected]",
      "firstName" : "some",
      "lastName" : "user2",
      "username" : "someuser2"
    }
}

This is what I got so far, I manage to get my head around with a string randomise function.

randomString(length) {
    return Math.round((Math.pow(36, length + 1) - Math.random() * Math.pow(36, length))).toString(36).slice(1);
}

And I would like to push my data into the object with random string as the name.

I tried string interpolation but it does not work.

var expensesObject = {
  uid: {
    amount: spentAmount,
    category: selectedCategory,
    date: formattedDate,
    time: formattedTime,
    note: note
  }
}

Possible duplicate of Access JSON or JS property using string — JAAulde
– JAAulde, Commented Mar 2, 2017 at 13:21
So your problem is actually generating the random number or using it as a key after generating it? — Alejandro Iván
– Alejandro Iván, Commented Mar 2, 2017 at 13:22

user4602228 · Accepted Answer · 2017-03-02 13:25:58Z

1

Consider this code

var users = {}

users[ randomString(20) ] = {
    amount   : spentAmount,
    category : selectedCategory,
    date     : formattedDate,
    time     : formattedTime,
    note     : note
}

answered Mar 2, 2017 at 13:25

user4602228

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Comments

Mehdi · Accepted Answer · 2017-03-02 13:33:18Z

1

You can do this by setting directly the object's key using []:

var expensesObject = {}

expensesObject[uid] = {
    amount: spentAmount,
    category: selectedCategory,
    date: formattedDate,
    time: formattedTime,
    note: note
}

edited Mar 2, 2017 at 13:33

answered Mar 2, 2017 at 13:21

Mehdi

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1 Comment

J.Doe Over a year ago

Nice approach! Thanks!

Nina Scholz · Accepted Answer · 2017-03-02 13:35:52Z

1

You could use a single random number for a distinct place. The check if lower or upper case.

Then assign to the new key the property of uid and delete the property.

function replaceUID(object) {
    object[random(28)] = object.uid;
    delete object.uid;
}

function random(size) {
    var r, s = '';
    while (s.length < size) {
        r = Math.floor(Math.random() * 62);
        s += r >= 36 ? (r - 26).toString(36).toUpperCase() : r.toString(36);
    }
    return s;
}

var expensesObject = { uid: { amount: 'spentAmount', category: 'selectedCategory',
date: 'formattedDate', time: 'formattedTime', note: 'note' } };

replaceUID(expensesObject);
console.log(expensesObject);

edited Mar 2, 2017 at 13:35

answered Mar 2, 2017 at 13:30

Nina Scholz

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1 Comment

J.Doe Over a year ago

I am not asking how to generate random string :)

Weedoze · Accepted Answer · 2017-03-02 13:21:21Z

0

Copy the object uid to a new object containing the random string

var expensesObject = {
  uid: {
    amount: 5,
    category: "catA",
    date: "02-03-2017",
    time: "14:00:00",
    note: "Notes"
  }
};

var finalobject = {};
let propertyName = randomString(10); //get the random string
finalobject[propertyName] = expensesObject.uid; //copy uid object
console.log(finalobject);

function randomString(length) {
  return Math.round((Math.pow(36, length + 1) - Math.random() * Math.pow(36, length))).toString(36).slice(1);
}

answered Mar 2, 2017 at 13:21

Weedoze

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4 Comments

JAAulde Over a year ago

I don't think the OP meant to literally replace uid as an existing property name on an existing object. The object in the final code sample is just an example of desired output

J.Doe Over a year ago

@Weedoze this is exactly what I'm looking for! Would the performance be dropping if we are to copy uid object? I'm dealing with large data set

Weedoze Over a year ago

@J.Doe You can try it yourself but I think that it won't be slow. What do you call large ? Don't forget to upvote the answer or mark it if it solved your problem

J.Doe Over a year ago

@Weedoze I'm trying an expenses app whereby users would add expenses object everyday. Will accept your answer in a sec, SO doesn't let me do that just yet :)

mvermand · Accepted Answer · 2017-03-02 13:22:19Z

0

You could do something like this:

function randomString(length) {
    return Math.round((Math.pow(36, length + 1) - Math.random() * Math.pow(36, length))).toString(36).slice(1);
}

var keylength = 16;  // <-- change as needed

var myObject = {
    amount: spentAmount,
    category: selectedCategory,
    date: formattedDate,
    time: formattedTime,
    note: note
  }

var expensesObject = {};

var uuid = randomString(keylength);

expensesObject[uuid]=myObject; // <-- use [ var_name ]

answered Mar 2, 2017 at 13:22

mvermand

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Comments

Vasilij Altunin · Accepted Answer · 2017-03-02 13:40:46Z

0

You also can create string and convert it to JSON object like this:

var expensesObjectStr = "{"+ '"'+ uid+'"'+": {"+
    '"amount"'+":"+ spentAmount+","+
    '"category"'+":"+'"'+ selectedCategory+'"'+","+
    '"date"'+": "+'"'+ formattedDate+'"'+","+
    '"time"'+": "+'"'+ formattedTime+'"'+","+
    '"note"'+": "+'"'+ note+'"'+
  "} }";

var obj = jQuery.parseJSON(expensesObjectStr);

Here small fiddle - https://jsfiddle.net/skyr9999/2dvffaty/

answered Mar 2, 2017 at 13:40

Vasilij Altunin

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Comments

Vadym Buhaiov · Accepted Answer · 2017-03-02 13:23:09Z

-2

var temp = expensesObject[uid];
expensesObject[randomString(<length>)] = temp;

answered Mar 2, 2017 at 13:23

Vadym Buhaiov

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1 Comment

Robert Over a year ago

Welcome to Stack!! could you please provide us some explanation? thank you

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