Serialize form data to JSON

I want to do some pre-server-validation of a form in a Backbone.js model. To do this I need to get the user input from a form into usable data. I found three methods to do this:

1. var input = $("#inputId").val();
2. var input = $("form.login").serialize();
3. var input = $("form.login").serializeArray();

Unfortunately, none of the provide a good reabable and developable JSON object which I require. I already looked through several questions on Stack Overflow, but I found only some extra libraries.

Doesn't Underscore.js, the current jQuery or Backbone.js provide a helper method?

I can't imagine there is no request for such a function.

HTML

<form class="login">
    <label for="_user_name">username:</label>
    <input type="text" id="_user_name" name="user[name]" value="dev.pus" />
    <label for="_user_pass">password:</label>
    <input type="password" id="_user_pass" name="user[pass]" value="1234" />
    <button type="submit">login</button>
</form>

JavaScript

var formData = $("form.login").serializeObject();
console.log(formData);

Outputs

{
    "name": "dev.pus",
    "pass": "1234"
}

Backbone.js model

var user = new User(formData);
user.save();

Here's a function for this use case:

function getFormData($form){
    var unindexed_array = $form.serializeArray();
    var indexed_array = {};

    $.map(unindexed_array, function(n, i){
        indexed_array[n['name']] = n['value'];
    });

    return indexed_array;
}

Usage:

var $form = $("#form_data");
var data = getFormData($form);

You can do this:

function onSubmit( form ){
  var data = JSON.stringify( $(form).serializeArray() ); //  <-----------

  console.log( data );
  return false; //don't submit
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<form onsubmit='return onSubmit(this)'>
  <input name='user' placeholder='user'><br>
  <input name='password' type='password' placeholder='password'><br>
  <button type='submit'>Try</button>
</form>

see this: http://www.json.org/js.html

The below code should help you out. :)

 //The function is based on http://css-tricks.com/snippets/jquery/serialize-form-to-json/
 <script src="//code.jquery.com/jquery-2.1.0.min.js"></script>

<script>
    $.fn.serializeObject = function() {
        var o = {};
        var a = this.serializeArray();
        $.each(a, function() {
            if (o[this.name]) {
                if (!o[this.name].push) {
                    o[this.name] = [o[this.name]];
                }
                o[this.name].push(this.value || '');
            } else {
                o[this.name] = this.value || '';
            }
        });
        return o;
    };

    $(function() {
        $('form.login').on('submit', function(e) {
          e.preventDefault();

          var formData = $(this).serializeObject();
          console.log(formData);
          $('.datahere').html(formData);
        });
    });
</script>

Use:

var config = {};
jQuery(form).serializeArray().map(function(item) {
    if ( config[item.name] ) {
		if ( typeof(config[item.name]) === "string" ) {
			config[item.name] = [config[item.name]];
		}
		config[item.name].push(item.value);
    } else {
		config[item.name] = item.value;
    }
});

I know this doesn't meet the helper function requirement, but the way I've done this is using jQuery's $.each() method

var loginForm = $('.login').serializeArray();
var loginFormObject = {};
$.each(loginForm,
    function(i, v) {
        loginFormObject[v.name] = v.value;
    });

Then I can pass loginFormObject to my backend, or you could create a userobject and save() it in backbone as well.

Trying to solve the same problem (validation without getting into complex plugins and libraries), I created jQuery.serializeJSON, that improves serializeArray to support any kind of nested objects.

This plugin got very popular, but in another project I was using Backbone.js, where I would like to write the validation logic in the Backbone.js models. Then I created Backbone.Formwell, which allows you to show the errors returned by the validation method directly in the form.

I couldn't find an answer that would solve this:

[{name:"Vehicle.Make", value: "Honda"}, {name:"Vehicle.VIN", value: "123"}]

This calls for this object:

{Vehicle: {Make: "Honda", "VIN": "123"}}

So I had to write a serializer of my own that would solve this:

function(formArray){
        var obj = {};
        $.each(formArray, function(i, pair){
            var cObj = obj, pObj, cpName;
            $.each(pair.name.split("."), function(i, pName){
                pObj = cObj;
                cpName = pName;
                cObj = cObj[pName] ? cObj[pName] : (cObj[pName] = {});
            });
            pObj[cpName] = pair.value;
        });
        return obj;
    }

Maybe it will help somebody.

If you do not care about repetitive form elements with the same name, then you can do:

var data = $("form.login").serializeArray();
var formData = _.object(_.pluck(data, 'name'), _.pluck(data, 'value'));

I am using Underscore.js here.

Here is what I use for this situation as a module (in my formhelper.js):

define(function(){
	FormHelper = {};

	FormHelper.parseForm = function($form){
		var serialized = $form.serializeArray();
		var s = '';
		var data = {};
		for(s in serialized){
			data[serialized[s]['name']] = serialized[s]['value']
		}
		return JSON.stringify(data);
	}

	return FormHelper;
});

It kind of sucks that I can't seem to find another way to do what I want to do.

This does return this JSON for me:

{"first_name":"John","last_name":"Smith","age":"30"}

If you are sending the form with JSON you must remove [] in the sending string. You can do that with the jQuery function serializeObject():

var frm = $(document.myform);
var data = JSON.stringify(frm.serializeObject());

$.fn.serializeObject = function() {
    var o = {};
    //    var a = this.serializeArray();
    $(this).find('input[type="hidden"], input[type="text"], input[type="password"], input[type="checkbox"]:checked, input[type="radio"]:checked, select').each(function() {
        if ($(this).attr('type') == 'hidden') { //if checkbox is checked do not take the hidden field
            var $parent = $(this).parent();
            var $chb = $parent.find('input[type="checkbox"][name="' + this.name.replace(/\[/g, '\[').replace(/\]/g, '\]') + '"]');
            if ($chb != null) {
                if ($chb.prop('checked')) return;
            }
        }
        if (this.name === null || this.name === undefined || this.name === '')
            return;
        var elemValue = null;
        if ($(this).is('select'))
            elemValue = $(this).find('option:selected').val();
        else elemValue = this.value;
        if (o[this.name] !== undefined) {
            if (!o[this.name].push) {
                o[this.name] = [o[this.name]];
            }
            o[this.name].push(elemValue || '');
        } else {
            o[this.name] = elemValue || '';
        }
    });
    return o;
}

Using Underscore.js:

function serializeForm($form){
    return _.object(_.map($form.serializeArray(), function(item){return [item.name, item.value]; }));
}

Using jQuery and avoiding serializeArray, the following code serializes and sends the form data in JSON format:

$("#commentsForm").submit(function(event){
	var formJqObj = $("#commentsForm");
	var formDataObj = {};
	(function(){
		formJqObj.find(":input").not("[type='submit']").not("[type='reset']").each(function(){
			var thisInput = $(this);
			formDataObj[thisInput.attr("name")] = thisInput.val();
		});
	})();
	$.ajax({
		type: "POST",
		url: YOUR_URL_HERE,
		data: JSON.stringify(formDataObj),
		contentType: "application/json"
	})
	.done(function(data, textStatus, jqXHR){
		console.log("Ajax completed: " + data);
	})
	.fail(function(jqXHR, textStatus, errorThrown){
		console.log("Ajax problem: " + textStatus + ". " + errorThrown);
	});
	event.preventDefault();
});

My contribution:

function serializeToJson(serializer){
    var _string = '{';
    for(var ix in serializer)
    {
        var row = serializer[ix];
        _string += '"' + row.name + '":"' + row.value + '",';
    }
    var end =_string.length - 1;
    _string = _string.substr(0, end);
    _string += '}';
    console.log('_string: ', _string);
    return JSON.parse(_string);
}

var params = $('#frmPreguntas input').serializeArray();
params = serializeToJson(params);

Well, here's a handy plugin for it: https://github.com/macek/jquery-serialize-object

The issue for it is:

> Moving ahead, on top of core serialization, .serializeObject will support correct serializaton for boolean and number values, resulting valid types for both cases. > >Look forward to these in >= 2.1.0

Found one possible helper:

https://github.com/theironcook/Backbone.ModelBinder

and for people who don't want to get in contact with forms at all: https://github.com/powmedia/backbone-forms

I will take a closer look at the first link and than give some feedback :)