karafka web ui, hide topic lags at 0 from tooltip

karafka_web_ui.user.js

// ==UserScript==
// @name         Karafka Web UI Fixes
// @description  Fixes some Karakfa Web UI annoyances
// @namespace    http://tampermonkey.net/
// @version      2024-12-03
// @author       Gonçalo Cabrita
// @match        *://*/karafka/dashboard*
// @updateURL    https://gist.github.com/gmcabrita/55568fcc1c4bd11f20b4f33980696555/raw/karafka_web_ui.user.js
// @downloadURL  https://gist.github.com/gmcabrita/55568fcc1c4bd11f20b4f33980696555/raw/karafka_web_ui.user.js
// @supportURL   https://gist.github.com/gmcabrita/55568fcc1c4bd11f20b4f33980696555#new_comment_field
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    function modifyChart(chart) {
        const originalFilter = chart.config.options.plugins.tooltip.filter;
        chart.config.options.plugins.tooltip.filter = function(tooltipItem, currentIndex, tooltipItems) {
            if (tooltipItem.raw[1] === 0) return false;
            return originalFilter ? originalFilter(tooltipItem, currentIndex, tooltipItems) : true;
        };
        chart.update('none');
    }

    // Monitor for new charts
    const observer = new MutationObserver((mutations) => {
        mutations.forEach((mutation) => {
            mutation.addedNodes.forEach((node) => {
                if (node.classList?.contains('chartjs-line')) {
                    const chart = Chart.getChart(node);
                    if (chart) {
                        modifyChart(chart);
                    }
                }
            });
        });
    });

    // Start observing
    observer.observe(document.body, {
        childList: true,
        subtree: true
    });

    // Modify existing charts
    document.querySelectorAll('.chartjs-line').forEach((node) => {
        const chart = Chart.getChart(node);
        if (chart) {
            modifyChart(chart);
        }
    });
})();