Converting strings like document.cookie to objects

Question

I have a string similiar to document.cookie:

var str = 'foo=bar, baz=quux';

Converting it into an array is very easy:

str = str.split(', ');
for (var i = 0; i < str.length; i++) {
    str[i].split('=');
}

It produces something like this:

[['foo', 'bar'], ['baz', 'quux']]

Converting to an object (which would be more appropriate in this case) is harder.

str = JSON.parse('{' + str.replace('=', ':') + '}');

This produces an object like this, which is invalid:

{foo: bar, baz: quux}

I want an object like this:

{'foo': 'bar', 'baz': 'quux'}

Note: I've used single quotes in my examples, but when posting your code, if you're using JSON.parse(), keep in your mind that it requires double quotes instead of single.

---

Update

Thanks for everybody. Here's the function I'll use (for future reference):

function str_obj(str) {
    str = str.split(', ');
    var result = {};
    for (var i = 0; i < str.length; i++) {
        var cur = str[i].split('=');
        result[cur[0]] = cur[1];
    }
    return result;
}

Answer 1

Why exactly do you need JSON.parse in here? Modifying your arrays example

let str = "foo=bar; baz=quux";

str = str.split('; ');
const result = {};
for (let i in str) {
    const cur = str[i].split('=');
    result[cur[0]] = cur[1];
}


console.log(result);

Answer 2

parse cookies (IE9+):

document.cookie.split('; ').reduce((result, v) => {
  const k = v.split('=');
  result[k[0]] = k[1];
  return result;
}, {})

Answer 3

A way to parse cookies using native methods like URLSearchParams and Object.fromEntries, avoiding loops and temporary variables.

Parsing document.cookie:

Object.fromEntries(new URLSearchParams(document.cookie.replace(/; /g, "&")))

For the scope of the question (cookies are separated by , and stored in variable str)

Object.fromEntries(new URLSearchParams(str.replace(/, /g, "&")))

Answer 4

The shortest way

 document.cookie.split('; ').reduce((prev, current) => {
    const [name, ...value] = current.split('=');
    prev[name] = value.join('=');
    return prev;
  }, {});

Answer 5

function getCookie(){
   var o=document.cookie.split("; ");
   var r=[{}];
   for(var i=0;i<o.length;i++){
      r[o[i].split("=")[0]] = o[i].split("=")[1];
   }
   return r;
}

Just call getCookie() and it will return all cookies from the current website. If you have a cookie called 'mycookie' you can run getCookie()['mycookie']; and it will return the value of the cookie 'mycookie'. There is also a One-Line option:

function getCookie(){var o=document.cookie.split("; ");var r=[{}];for(var i=0;i<o.length;i++){r[o[i].split("=")[0]] = o[i].split("=")[1];}return r;}

This one can be used with the same methods as above.

Answer 6

Most of the above solutions fail with the __gads cookie that Google sets because it uses a '=' character in the cookie value.

The solution is to use a regular expression instead of calling split('='):

document.cookie.split(';').reduce((prev, current) => {
  const [name, value] = current.split(/\s?(.*?)=(.*)/).splice(1, 2);
  prev[name] = value;
  return prev;
}, {});

Answer 7

first thing that occurred to me, I'll leave it as the original version, but cookies should not be empty otherwise there will be a json parse error

JSON.parse(`{"${document.cookie.replace(/=/g,'":"').replace(/; /g,'","')}"}`)

fast and reliable version - cookie to object

let c=document.cookie.split('; '),i=c.length,o={};
while(i--){let a=c[i].split('=');o[a[0]]=a[1]}

and short function for get single cookie

getCookie=e=>(e=document.cookie.match(e+'=([^;]+)'),e&&e[1])

Answer 8

note : The document.cookie (question headline) is semicolon separated and not comma separated (question) ...

An alternative using reduce :

var str = 'foo=bar; baz=quux';
var obj = str.split(/[;] */).reduce(function(result, pairStr) {
  var arr = pairStr.split('=');
  if (arr.length === 2) { result[arr[0]] = arr[1]; }
  return result;
}, {});

Answer 9

An alternate version of your updated solution that checks for the null/empty string and just returns an empty object and also allows for custom delimiters.

function stringToObject(str, delimiter) {
    var result = {};
    if (str && str.length > 0) {
        str = str.split(delimiter || ',');
        for (var i = 0; i < str.length; i++) {
            var cur = str[i].split('=');
            result[cur[0]] = cur[1];
        }
    }
    return result;
}

Answer 10

I'm a fan of John Resig's "Search and don't replace" method for this sort of thing:

var str = 'foo=bar, baz=quux',
    arr = [],
    res = '{';

str.replace(/([^\s,=]+)=([^,]+)(?=,|$)/g, function ($0, key, value) { 
    arr.push('"' + key + '":"' + value + '"');
});

res += arr.join(",") + "}";

alert(res);

Working example: http://jsfiddle.net/cm6MT/.

Makes things a lot simpler without the need for JSON support. Of course, it's just as easy to use the same regular expression with exec() or match().

---

Whoops, I thought you wanted to convert to a JSON string, not an object. In that case, you only need to modify the code slightly:

var str = 'foo=bar, baz=quux',
    res = {};

str.replace(/([^\s,=]+)=([^,]+)(?=,|$)/g, function ($0, key, value) { 
    res[key] = value;
});
console.log(res.foo);
//-> "bar"

Working example 2: http://jsfiddle.net/cm6MT/1/

Answer 11

That's pretty crappy data, as long as its not using ,= this would work on that data

var text = 'foo=bar, baz=quux',
    pattern = new RegExp(/\b([^=,]+)=([^=,]+)\b/g),
    obj = {};

while (match = pattern.exec(text)) obj[match[1]] = match[2];

console.dir(obj);

Answer 12

To convert it to an object, just do that from the beginning:

var obj = {};
str = str.split(', ');
for (var i = 0; i < str.length; i++) {
    var tmp = str[i].split('=');
    obj[tmp[0]] = tmp[1];
}

Then, if you want JSON out of it:

var jsonString = JSON.stringify(obj);

Answer 13

Given an array a containing your intermediate form:

[['foo', 'bar'], ['baz', 'quux']]

then simply:

var obj = {};
for (var i = 0; i < a.length; ++i) {
   var tmp = a[i];
   obj[tmp[0]] = tmp[1];
}