time.js

const cookiedata = {};
document.cookie.split("; ").forEach(elem => {
  const arr = elem.split("=");
  cookiedata[arr[0]] = decodeURIComponent(arr[1]);
});
console.log(cookiedata);
/**
 * @param {Date} date
 * @param {string} text
 */
function format(date, text) {
  const replaceData = {
    "ALL": "toLocaleString",
    "YE": "getFullYear",
    "MO": date.getMonth() + 1,
    "DA": "getDate",
    "HO": "getHours",
    "MI": "getMinutes",
    "SE": "getSeconds",
    "MS": "getMilliseconds",
    "UALL": "toString",
    "UYE": "getUTCFullYear",
    "UMO": date.getUTCMonth() + 1,
    "UDA": "getUTCDate",
    "UHO": "getUTCHours",
    "UMI": "getUTCMinutes",
    "USE": "getUTCSeconds",
    "UMS": "getUTCMilliseconds",
    "%": "%",
  };
  Object.keys(replaceData).forEach(target => {
    const value = replaceData[target];
    target = "%" + target;
    if (typeof value === "string") {
      text = text.replaceAll(target, date[value]());
    } else {
      text = text.replaceAll(target, value(date));
    }
  });
  return text;
}
chrome.storage.local.get(async function (value) {
  const terget = value.terget;
  const date = new Date();
  const data = format(date, value.data);
  fetch(`https://scratch.mit.edu/site-api/users/all/${(await (await fetch("https://scratch.mit.edu/session/", { "headers": { "x-requested-with": "XMLHttpRequest" } })).json()).user.username}/`, {//意見もらったんで少し改造
    "headers": {
      "x-csrftoken": cookiedata.scratchcsrftoken,
      "x-requested-with": "XMLHttpRequest"
    },
    "body": `{"${terget}":"${data}"}`,
    "method": "PUT",
  });
});