postman-script.js

const $ = cheerio.load(pm.response.text())

const ele = $('form input[type="hidden"]');

const csrf_token = ele.val();

console.log(csrf_token);

const loginRequest = {
    url: 'https://a0f2a3f3-f800-40ba-8578-248561f0b0f8.mock.pstmn.io/login',
    method: 'POST',
    header: {
        'Content-Type': 'application/x-www-form-urlencoded'
    },
    body: {
        mode: 'urlencoded',
        urlencoded: [
            {key: "username", value: "eryan", diabled: false},
            {key: "password", value: "eryan", diabled: false},
            {key: "csrf", value: csrf_token, diabled: false}
        ]
    }
}

pm.sendRequest(loginRequest, function(err, res) {
   var playSession = res.headers.find(h => h.key === "Set-Cookie" && h.value.includes("PLAY_SESSION"));
   var kv = playSession.value.split("=");
   console.log(kv);
});