If your object looks like:

myObject = {"value": " this is a string"};

You don't need to stringify to get the string value, you can use this instead:

myObject.value

This simple regular expression solution works to unquote JSON property names in most cases:

const object = { name: 'John Smith' };
const json = JSON.stringify(object);  // {"name":"John Smith"}
console.log(json);
const unquoted = json.replace(/"([^"]+)":/g, '$1:');
console.log(unquoted);  // {name:"John Smith"}

Extreme case:

var json = '{ "name": "J\\":ohn Smith" }'
json.replace(/\\"/g,"\uFFFF");  // U+ FFFF
json = json.replace(/"([^"]+)":/g, '$1:').replace(/\uFFFF/g, '\\\"');
// '{ name: "J\":ohn Smith" }'

Special thanks to Rob W for fixing it.

Limitations

In normal cases the aforementioned regexp will work, but mathematically it is impossible to describe the JSON format with a regular expression such that it will work in every single cases (counting the same number of curly brackets is impossible with regexp.) Therefore, I have create a new function to remove quotes by formally parsing the JSON string via native function and reserialize it:

function stringify(obj_from_json) {
    if (typeof obj_from_json !== "object" || Array.isArray(obj_from_json)){
        // not an object, stringify using native function
        return JSON.stringify(obj_from_json);
    }
    // Implements recursive object serialization according to JSON spec
    // but without quotes around the keys.
    let props = Object
        .keys(obj_from_json)
        .map(key => `{stringify(obj_from_json[key])}`)
        .join(",");
    return `{${props}}`;
}

Example: https://jsfiddle.net/DerekL/mssybp3k/

The data just needs a bit of massaging

var data = {
    "question1": {
        "Reliable": true,
        "Knowledgeable": false,
        "Helpful": true,
        "Courteous": true
    },
    "question2": {
        "checked": "Extremely Well"
    },
    "question3": {
        "checked": "Extremely Well"
    },
    "question4": {
        "checked": 3
    },
    "fullName": "Test",
    "address": "Test",
    "city": "Test",
    "state": "Test",
    "zip": "321",
    "areaCode": "321",
    "phone": 1234567896,
    "call": true,
    "lifeInsurance": "Yes",
    "brokerage": "Yes",
    "bankName": "Regions"
};

var result = Object.entries(data).reduce((result, [key, value]) => {
    key = key.replace(/([A-Z]|\d+)/g, ' $1').replace(/^(.)/, (unused, p1) => p1.toUpperCase());
    if (!['string', 'number', 'boolean'].includes(typeof value)) {
        value = Object.entries(value).map(([key, value]) => (typeof value == 'boolean') ? (value ? key : undefined) : value).filter(v => v !== undefined).join(',');
    }
    result.push(`${key}: ${value}`);
    return result;
}, []);
console.log(result.join('\n'));

Note: I changed one of the true to false to check the logic

Tested in node 8.1.2

JSON.stringify(dataArray) will always return square brackets because dataArray is of type array. Instead, you could stringify each element of your array, then join them separated by commas.

dataArray = dataArray.map(function(e){
  return JSON.stringify(e);
});

dataString = dataArray.join(",");

Then

["newData",4,2]

becomes

"newData",4,2

Addendum: Please don't try to replace() out the brackets manually because it could be that one day a bracket enters your array in a string. e.g. ["Please see ref[1]",4,2]

Javascript strings are immutable. When you call blah2.replace, you are not replacing something inside blah2, you are creating a new string. What you probably want is:

blah2 = blah2.replace(/[{}]/g, '');

You can use regex to remove []{} characters: str.replace(/[\[\]\{\}]+/g, '').

You can continue to escape other characters such as quotes if that's what you're looking for.

change $products[] = to $products = in your for each loop, that should fix the extra square brackets. And if you want to get all entries and their titleVariation fields you should use 'elementType' => Entry::Class

'pricelist/<entryId:\d+>.json' => function($entryId) {
    return [
        'elementType' => Entry::Class,
        'criteria' => [
            'section' => 'products',
            'descendantOf' => $entryId,
        ],
        'transformer' => function(Entry $entry) {

            $products = [];
            // "orderItem" is entry field
            foreach ( $entry->orderItem as $product ) {
                $products = [
                    'title' => $product->titleVariation,
                ];
            }
            return $products;
        },
    ];
},

Use this when you return:

return properties[0];

Or

var data = [

{
    "Name": "TEST",
    "deviceId": "",
    "CartId": "",
    "timestamp": 1383197265540,
    "FOOD": [],
    "City": "LONDON CA"
 }

]; // Or whatever the Json is
data = data[0];

Or if you're accessing the json via another object

var data = jsonObj[0];

As I said in the comments, you need a for...in ^[MDN] loop to iterate over the properties of the object and can use recursion to subsequently convert nested objects:

function convert(obj, prefix, result) {
    result = result || {};

    // iterate over all properties
    for (var prop in obj) {
        if (obj.hasOwnProperty(prop)) {
            var value = obj[prop];
            // build the property name for the result object
            // first level is without square brackets
            var name = prefix ? prefix + '[' + prop + ']' : prop;
            if (typeof value !== 'object') {
                // not an object, add value to final result
                result[name] = value;
            }
            else {
                // object, go deeper
                convert(value, name, result);
            }
        }
    }

    return result;
}

// Usage:
var converted_data = convert(data);

DEMO

Still, I would recommend using JSON.

If you want to handle files as well, you might have to add an additional check for File objects. You'd want them raw in the result object:

else if (window.File && value instanceof File) {
    result[name] = value;
}

// and for file lists

else if (window.FileList && value instanceof FileList) {
    for (var i = 0, l = value.length; i < l; i++) {
        result[name + '[' + i + ']'] = value.item(i);
    }
}

It could be that the File (FileList) constructor is named differently in IE, but it should give you a start.