Add type checking for cookies value

[greg2012201]

Hello!

I have fixed a bug regarding this issue #66. After this fix, the bug described in the mentioned issue shouldn't appear anymore.

[andreizanik]

Hi, thanks for your PR but I think we have a problem with setCookie function and only on backend side.

For example, if we run this code on frontend side everything will be ok

setCookie('MY_TEST_COOKIE', true);
console.log('MY TEST COOKIE HERE', getCookie('MY_TEST_COOKIE'));

and

console.log(typeof getCookie('MY_TEST_COOKIE')) === string 

I think we need to figure out why a boolean value is set and not a string

[andreizanik]

I figured it out a little and I think the problem is in line 109
It seems we need to use stringify function

const payload = { name: key, value: stringify(data), ...restOptions };

like in 132 line

const cookieStr = serialize(key, stringify(data), { path: '/', ..._cookieOptions });

What do you think about it?

[greg2012201]

Thank you for the review!🙌 I understand your perspective. In this PR (after my changes), setting cookies as a boolean or even another type like a number works correctly: the value is being set (server-side), and you can easily get it (server-side), but only with the same type as it was set with. Let's examine these examples:

// 1
setCookie("MY_TEST_COOKIE", true, { req });
    console.log("MY TEST COOKIE HERE", typeof getCookie("MY_TEST_COOKIE", { req })); // boolean
// 2    
 setCookie("MY_TEST_COOKIE", 10, { req });
    console.log("MY TEST COOKIE HERE", typeof getCookie("MY_TEST_COOKIE", { req })); // number
// 3    
setCookie("MY_TEST_COOKIE", 'test string', { req });
    console.log("MY TEST COOKIE HERE", typeof getCookie("MY_TEST_COOKIE", { req })); // string

Setters and getters use cookies from next/headers and the req object from Next.js. They also behave accordingly.

Therefore, my proposal is to merge this PR as a fix for setting values server-side and either modify the rest of the codebase to adhere to the native Next.js behavior or parse every type of value to string.

[andreizanik]

Sorry for delay.

Cookies value is always string.
Your example works as you say because you try to set and to get cookies during one request

For example. Let's imagine two API endpoints

// api/set-cookie.ts 
export const GET = async (req: NextRequest) => {
      const res = new NextResponse();
      setCookie('test', true, { res, req });
      console.log(typeof getCookie('test', { res, req })); // ---> boolean
      return res;
};

// api/get-cookie.ts 
export const GET = async (req: NextRequest) => {
      const res = new NextResponse();
      console.log(typeof getCookie('test', { res, req })); // ---> string
      return res;
};

I think this behavior can lead unexpected results so better way is to always set string and always get string

Also, without "app router" this library transform value to string before setting. It will be better to keep the same behavior for different cases.

[greg2012201]

Ok I got It! 🙌 I have submitted another PR where all values are set as strings. Please check it out and test it -> #69

[andreizanik]

So I think this PR should be closed