Added function to calculate cumulative GPA(including unfinished semesters)

src/js/helpers.js

@@ -104,7 +104,7 @@ function calculate_gpa (courses) {
     let sum = 0;
     for (var i = 0; i < courses.length; i++) {
         if (gradeToGPA(courses[i].grade) !== -1) {
-            const multiplier = total_add(courses[i].name);
+            const multiplier = calculate_credit_hours(courses[i].name);
             courses_with_grades += multiplier;
             sum += multiplier * (gradeToGPA(courses[i].grade) + course_boost(courses[i].name, courses[i].grade));
         }
@@ -113,16 +113,7 @@ function calculate_gpa (courses) {
         return '0.00';
     }
     return (sum / courses_with_grades).toFixed(2);
-    function total_add (course_name) {
-        const double_effect_courses = [`English 10/American History`, `English 9/World History`];
-        if (double_effect_courses.includes(course_name)) {
-            return 2;
-        }
-        if (/^(I Service: |IS: )/.test(course_name)) {
-            return 0.5;
-        }
-        return 1;
-    }
+
     function course_boost (course_name, grade) {
         if (gradeToGPA(grade) < 1.8) {
             return 0;
@@ -134,6 +125,17 @@ function calculate_gpa (courses) {
     }
 }
 
+function calculate_credit_hours (course_name) {
+    const double_effect_courses = [`English 10/American History`, `English 9/World History`];
+    if (double_effect_courses.includes(course_name)) {
+        return 2;
+    }
+    if (/^(I Service: |IS: )/.test(course_name)) {
+        return 0.5;
+    }
+    return 1;
+}
+
 /**
  * Extract the final percent from the course page html.
  * @param {String} html course page html
@@ -184,4 +186,5 @@ export {
     calculate_gpa,
     extractFinalPercent,
     assignments,
+    calculate_credit_hours,
 };

src/js/models/Course.js

@@ -21,13 +21,15 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  *
  */
+import { calculate_credit_hours } from '../helpers';
 
 export default class Course {
     #name;
     #grade;
     #finalPercent;
     #link;
     #assignments;
+    #creditHour;
 
     /**
      * Create new course instance
@@ -37,19 +39,25 @@ export default class Course {
      * @param {String} [grade] current grade for the course
      * @param {Number?} [finalPercent] current final percent of the course
      * @param {Assignment[]} [assignments] number of missing assignments
+     * @param {Number?} [creditHour] number of credit hours this course counts for, optional
      */
     constructor (name, link, grade, finalPercent, assignments) {
         this.#name = name;
         this.#link = link;
         this.#grade = grade;
         this.#finalPercent = finalPercent;
         this.#assignments = assignments;
+        this.#creditHour = calculate_credit_hours(this.#name);
     }
 
     get name () {
         return this.#name;
     }
 
+    get creditHour () {
+        return this.#creditHour;
+    }
+
     get link () {
         return this.#link;
     }
@@ -62,6 +70,10 @@ export default class Course {
         this.#grade = g;
     }
 
+    set creditHour (c) {
+        this.#creditHour = c;
+    }
+
     get finalPercent () {
         return this.#finalPercent;
     }

src/js/saspowerschoolff.js

@@ -2,6 +2,8 @@
  *
  * @copyright Copyright (c) 2018-2020 Gary Kim <gary@garykim.dev>
  *
+ * @copyright Copyright (c) 2020 Suhas Hariharan <mail@suhas.net>
+ *
  * @author Gary Kim <gary@garykim.dev>
  *
  * @license GNU AGPL version 3 only
@@ -70,6 +72,7 @@ function analytics_message (action_input) {
     const href = window.location.href.split("?")[0];
     browser.runtime.sendMessage({ action: "analytics_send", args: { url: href, action: action_input } });
 }
+
 function main_page () {
     const student_name = document.querySelector('#userName').querySelector('span').innerText;
     let second_semester = false;
@@ -128,6 +131,7 @@ function main_page () {
         }
     }
     $("table[border='0'][cellpadding='3'][cellspacing='1'][width='100%']").prepend(`<tr><td align="center">Current Semester GPA (${second_semester ? 'S2' : 'S1'}): ${calculate_gpa(courses)}</td></tr>`);
+
     if (second_semester) {
         fetch("https://powerschool.sas.edu.sg/guardian/termgrades.html")
             .then((response) => {
@@ -151,6 +155,11 @@ function main_page () {
                 }
             });
     }
+    $("table[border='0'][cellpadding='3'][cellspacing='1'][width='100%']").prepend(`<td style="background-color: white;" align="center"><button id="calculateCumulative">Calculate Cumulative GPA</button></td>`);
+    // passing courses in to possibly include current semester GPA if term has not finished yet.
+    $("#calculateCumulative").click(function () {
+        show_cumulative_gpa(courses);
+    });
     // Hypo Grade Calculator
     const HypoGradesDiv = document.createElement('div');
     HypoGradesDiv.classList.add("hypo-grade-div-fixed");
@@ -162,6 +171,12 @@ function main_page () {
         },
     }).$mount(".hypo-grade-div-fixed");
 }
+function show_cumulative_gpa (courses) {
+    $("#calculateCumulative").hide();
+    calculate_cumulative_gpa(courses).then(cumulative_gpa => {
+        $("table[border='0'][cellpadding='3'][cellspacing='1'][width='100%']").prepend(`<tr><td align="center">Cumulative GPA(9-12): ${cumulative_gpa.toFixed(2)}</td></tr>`);
+    });
+}
 function class_page () {
     // Show final percent
     const number = extractFinalPercent($("table.linkDescList").html());
@@ -188,6 +203,85 @@ function login_page () {
     });
 }
 
+function calculate_cumulative_gpa (current_courses) {
+    const list_of_gpas = [];
+    const all_courses = [];
+    const credit_hour_list = [];
+    let element_list = [];
+    const fetches = [];
+    // Fetches grade history page
+    const gpas = fetch("https://powerschool.sas.edu.sg/guardian/termgrades.html")
+        .then(response => response.text())
+        .then(data => {
+            const el = document.createElement("html");
+            el.innerHTML = data;
+            const tabs = el.getElementsByClassName("tabs")[0].getElementsByTagName("li");
+            // Iterate until the end of tabs or until no longer at a high school semester.
+            for (let i = 0; i < tabs.length && /HS$/.test(tabs[i].innerText); i++) {
+                fetches.push(
+                    fetch(tabs[i].getElementsByTagName("a")[0].href)
+                        .then(res => res.text())
+                        .then(function (data2) {
+                            let courses = [];
+                            const semester = document.createElement("html");
+                            semester.innerHTML = data2;
+                            element_list = semester.getElementsByClassName("box-round")[0].getElementsByTagName("table")[0];
+                            element_list = element_list.getElementsByTagName("tbody")[0].getElementsByTagName("tr");
+                            for (let t = 2; t < element_list.length; t++) {
+                                if (element_list[t].innerText.trim() === ("S2")) {
+                                    all_courses.push(courses);
+                                    courses = [];
+                                }
+                                if (element_list[t].getElementsByTagName("th").length > 0) {
+                                    continue;
+                                } else {
+                                    const $prev_course = element_list[t];
+                                    // Creates course object with each course from grade history page
+                                    const course = new Course($prev_course.getElementsByTagName("td")[0].textContent.trim(), "",
+                                        $prev_course.getElementsByTagName("td")[1].textContent.trim(), 0, "");
+
+                                    courses.push(course);
+                                }
+                            }
+                            all_courses.push(courses);
+                        }));
+            }
+            // Calculates cumulative GPA based on credit hours per semester and gpa for each semester.
+            let include_current_semester = false;
+            if (current_courses.length !== 0) {
+                for (let i = 0; i < current_courses.length; i++) {
+                    if (current_courses[i].link.includes("begdate")) {
+                        include_current_semester = true;
+                    }
+                }
+            }
+            if (include_current_semester) {
+                all_courses.push(current_courses);
+            }
+            const cumulative_gpa = Promise.all(fetches).then(function () {
+                let total_count = 0;
+                let total_gpa = 0;
+                for (let i = 0; i < all_courses.length; i++) {
+                    let count = 0;
+                    list_of_gpas.push(calculate_gpa(all_courses[i]));
+                    for (let t = 0; t < all_courses[i].length; t++) {
+                        count += all_courses[i][t].creditHour;
+                    }
+                    // Adds all credit hours to overall credit hour count
+                    total_count += count;
+                    // Adds each amount of credit hours per semester to list
+                    credit_hour_list.push(count);
+                }
+                for (let i = 0; i < all_courses.length; i++) {
+                    total_gpa += ((credit_hour_list[i] / total_count) * list_of_gpas[i]);
+                }
+                return (total_gpa);
+            });
+            return cumulative_gpa;
+        });
+    return gpas;
+}
+
 function html2node (html_string) {
     return html2nodelist(html_string)[0];
 }