Convert Home Assistant Supervisor Logs from UTC to Local Time

homeassistant-supervisor-log.user.js

// ==UserScript==
// @name         Home Assistant Supervisor Logs UTC to local time
// @namespace    https://github.com/d-alleyne/
// @version      0.3
// @description  A script to convert Home Assistant Supervisor logs from UTC to local time. Now supports Chrome.
// @author       Damien Alleyne
// @match        http://homeassistant.local:8123/hassio/system
// @grant        none
// ==/UserScript==

const convertUTCToLocal = (entry) => {
  const dateRegex = /^(\d{2})\-(\d+)\-(\d+) (\d+):(\d+):(\d+)/;
  let utcTime = entry.innerText.match(dateRegex);

  if (utcTime?.length) {
    const [_, year, month, day, hour, minute, second] = utcTime;
    // + operator to convert string to number. See https://javascript.info/operators#numeric-conversion-unary
    const date = new Date(
      Date.UTC(+year + 2000, +month - 1, day, hour, minute, second)
    );
    const localDate = new Intl.DateTimeFormat("en", {
      dateStyle: "medium",
      timeStyle: "short",
    }).format(date);
    entry.innerText = entry.innerText.replace(dateRegex, localDate);
  }
};

(function () {
  //the JS Path for the Supervisor logs is different between Chromium-based and Gecko-based browsers
  const isGecko = window.navigator.userAgent.match(/Gecko\/\d{8}/);
  let counter = 0;
  let mainTimer = setInterval(() => {
    try {
      const mainBox = isGecko
        ? document.querySelector("body > hassio-main")
        : document
            .querySelector("body > home-assistant")
            .shadowRoot.querySelector("home-assistant-main")
            .shadowRoot.querySelector(
              "app-drawer-layout > partial-panel-resolver > ha-panel-custom > iframe"
            )
            .contentDocument.querySelector("body > hassio-main");

      const supervisorLog = mainBox?.shadowRoot
        .querySelector("hassio-router > hassio-panel")
        ?.shadowRoot.querySelector("hassio-panel-router > hassio-system")
        ?.shadowRoot.querySelector(
          "hass-tabs-subpage > div > hassio-supervisor-log"
        );

      if (supervisorLog) {
        const htmlBox = supervisorLog.shadowRoot.querySelector(
          "#content > hassio-ansi-to-html"
        );
        const logBox = htmlBox?.shadowRoot.querySelectorAll("pre > span");
        if (logBox) {
          clearInterval(mainTimer);
          logBox.forEach(convertUTCToLocal);
        } //if (logBox)
      }
    } catch (err) {
      // element doesn't exist yet?
      console.log(err);
      // we should have found the element by now
      if (++counter > 50) {
        clearInterval(mainTimer);
      }
    }
  }, 300);
})();