Helper function for dealing with cakephp form fields. Requires Lodash and jQuery.

README.md

Example:

HTML:

<form id="myForm">
    <label for="PermissionsWrite">Write</label>
    <input id="PermissionsWrite" type="checkbox" name="data[Permissions][]" value="Write" checked />
    
    <label for="PermissionsRead">Read</label>
    <input id="PermissionsRead" type="checkbox" name="data[Permissions][]" value="Read" />
    
    <label for="PermissionsLevel">Level</label>
    <input type="text" name="data[Permissions][level]" id="PermissionsLevel" value="admin" />
</form>

Javascript

CakePHP.Form.toJSON(document.getElementById('myForm'))
// "{"data[Permissions]":["Write"],"data[Permissions][level]":"admin"}"

cakephp.js

var CakePHP = {

    Form : {

        parseIntoTree : function(name, value) {
            if (typeof name !== 'string') {
                return {};
            }

            var nameParts = name.split('[]');

            return (function buildTreePart(val, idx) {
                var part = nameParts[idx];

                if (part.length) {
                    part = [_.zipObject([part], [val])];
                } else {
                    part = [val];
                }

                if (!idx) {
                    return part;
                } else {
                    return buildTreePart(part, idx - 1);
                }

            })(value, nameParts.length - 1)[0];
        },

        mergeTree : function(treeOne, treeTwo) {
            if (_.isArray(treeOne) && _.isArray(treeTwo)) {
                return treeOne.concat(treeTwo);
            }

            if (!_.isObject(treeOne) || !_.isObject(treeTwo)) {
                return treeTwo;
            }

            return _.reduce(treeTwo, function(object, value, key) {
                if (typeof object[key] !== 'undefined') {
                    value = CakePHP.Form.mergeTree(object[key], treeTwo[key]);
                }

                object[key] = value;

                return object;
            }, treeOne);
        },

        toJSON : function(node) {
            return JSON.stringify(CakePHP.Form.toData(node));
        },

        getInputNodes : function(node) {
            return $('input, textarea', node);
        },

        toData : function(formNode) {
            return _.reduce(this.getInputNodes(formNode), function(object, inputNode) {
                var $inputNode = $(inputNode);

                if ($inputNode.attr('type') === 'checkbox' && !$inputNode.is(':checked')) {
                    return object;
                }

                return CakePHP.Form.mergeTree(
                    object,
                    CakePHP.Form.parseIntoTree($inputNode.attr('name'), $inputNode.val())
                );
            }, {});
        }
    }
};