Registro Elettronico Spaggiari Enanched.user.js

/* jshint esnext: true */

// ==UserScript==
// @name         Registro Elettronico Spaggiari Enanched
// @namespace    https://web.spaggiari.eu/
// @version      0.1
// @description  New functions for the grade page.
// @author       daw
// @match        https://web.spaggiari.eu/cvv/app/default/genitori_voti.php
// @grant        none
// @require http://code.jquery.com/jquery-2.1.4.min.js
// ==/UserScript==

function grade_to_float(grade) {
    let table = {"10": 10,
                 "9/10": 9.75,
                 "9½": 9.5,
                 "9+": 9.25,
                 "9": 9,
                 "8/9": 8.75,
                 "8½": 8.5,
                 "8+": 8.25,
                 "8": 8,
                 "7/8": 7.75,
                 "7½": 7.5,
                 "7+": 7.25,
                 "7": 7,
                 "6/7": 6.75,
                 "6½": 6.5,
                 "6+": 6.25,
                 "6": 6,
                 "5/6": 5.75,
                 "5½": 5.5,
                 "5+": 5.25,
                 "5": 5,
                 "4/5": 4.75,
                 "4½": 4.5,
                 "4+": 4.25,
                 "4": 4,
                 "3/4": 3.75,
                 "3½": 3.5,
                 "3+": 3.25,
                 "3": 3,
                 "2/3": 2.75,
                 "2½": 2.5,
                 "2+": 2.25,
                 "2": 2
    };
    return table[grade];
}

function createElem(mean) {
    let meanElement=document.createElement('td');

    meanElement.textContent = mean.toPrecision(4);
    meanElement.width="350";
    meanElement.classList.add("registro");
    meanElement.classList.add("grautext");
    meanElement.classList.add("open_sans_condensed_bold");
    meanElement.classList.add("font_size_14");
    meanElement.style="vertical-align: middle;";
    meanElement.align="left";

    return meanElement;
}

let grades = $('#data_table_2 tr').slice(4).map(function() {
    return $(this).find('.q3').find('p').map(function () {
        return $(this).text();});
});

let table = $('#data_table_2 tr').slice(4);

// Foreach subject
for (let i = 0; i<grades.length; i++){
    //real_grades = subject.filter( (i) => subject[i] !== "");
    let subject = grades[i];
    let real_grades = subject.filter( (i) => subject[i] !== "").toArray();

    real_grades = real_grades.map(grade_to_float);
    if (real_grades.length === 0) continue;
    let mean = real_grades.reduce( (a,b) => a+b, 0)/real_grades.length;

    table[i].appendChild(createElem(mean));
    console.log(mean);
}