Use percent change when viewing futures on Bloomberg

bloomberg-futures.userscript.js

// ==UserScript==
// @name         Bloomberg Futures
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Chage table content to use percents for futures
// @author       Jared Rummler
// @match        https://www.bloomberg.com/markets/stocks/futures
// @grant        none
// ==/UserScript==

'use strict';

const NET_CHANGE_INDEX = 4;
const TOTAL_POINTS_INDEX = 3;

(function() {
    function cell(row, index) {
        return row.getElementsByClassName("data-table-row-cell")[index];
    }

    function parseCellToFloat(cell) {
        return parseFloat(cell.textContent.replace(',', ''));
    }

    // Get the tables containing market data for each region
    const tables = document.getElementsByClassName("data-table");
    for (let i = 0, table; table = tables[i]; i++) {
        const rows = table.getElementsByClassName("data-table-row");
        for (let j = 0, row; row = rows[j]; j++) {
            const netChangeCell = cell(row, NET_CHANGE_INDEX);
            const netChangeInPoints = parseCellToFloat(netChangeCell);
            const openPoints = parseCellToFloat(cell(row, TOTAL_POINTS_INDEX));
            const percent = ((netChangeInPoints / openPoints) * 100);
            netChangeCell.setAttribute("data-type", (percent > 0) ? "better" : "worse");
            netChangeCell.getElementsByClassName("data-table-row-cell__value")[0].textContent = percent.toFixed(2) + '%';
        }
    }
})();